diff --git a/doc/arm/Bv9ARM.1.html b/doc/arm/Bv9ARM.1.html index 8ee620c673..63da8dc812 100644 --- a/doc/arm/Bv9ARM.1.html +++ b/doc/arm/Bv9ARM.1.html @@ -1,89 +1,71 @@ - - - - Section 1. Introduction +

    Section 1. Introduction

    +

The Internet Domain Name System (DNS) consists of the syntax to specify the names of entities in the Internet in a hierarchical manner, the rules used for delegating authority over names, and the system implementation that actually maps names to Internet addresses. DNS data is maintained in a group of distributed hierarchical databases.

- +

    1.1 Scope of Document

    - +

The Berkeley Internet Name Domain (BIND) implements an Internet nameserver for a number of operating systems. This document provides basic information about the installation and care of the Internet Software Consortium (ISC) BIND version 9 software package for system administrators.

- +

    1.2 Organization of This Document

    - +

- + -In this document, -Section 1 - introduces the basic DNS and BIND concepts. -Section 2 - describes resource requirements for running BIND in various environments. Information in -Section 3 +In this document, +Section 1 + introduces the basic DNS and BIND concepts. +Section 2 + describes resource requirements for running BIND in various environments. Information in +Section 3 is task-oriented - in its presentation and is organized functionally, to aid in the process of installing the BINDv9 software. The task-oriented section is followed by -Section 4 -, which contains more advanced concepts that the system administrator may need for implementing certain options. The contents of -Section 5 - are organized as in a reference manual to aid in the ongoing maintenance of the software. -Section 6 - addresses security considerations, and -Section 7 - contains troubleshooting help. The main body of the document is followed by several -Appendices + in its presentation and is organized functionally, to aid in the process of installing the BIND 9 software. The task-oriented section is followed by +Section 4 +, which contains more advanced concepts that the system administrator may need for implementing certain options. Section 5 describes the BIND 9 lightweight resolver. The contents of +Section 6 + are organized as in a reference manual to aid in the ongoing maintenance of the software. +Section 7 +addresses security considerations, and +Section 8 + contains troubleshooting help. The main body of the document is followed by several +Appendices which contain useful reference information, such as a -Glossary - and a Bibliography -, as well as historic information related to BIND and the Domain Name System.

+ and historic information related to BIND and the Domain Name System.

+

    1.3 Conventions Used in This Document

    - +

@@ -207,8 +189,8 @@ keywords

- -Sans Serif Bold + +Sans Serif Bold

@@ -293,12 +275,12 @@ Text is enclosed in square brackets

- +

    1.4 Discussion of Domain Name System (DNS) Basics and BIND

    - +

@@ -316,12 +298,12 @@ resolver resolver is a set of routines residing in a system library that provides the interface that programs can use to access the domain name services.

- +

    1.4.1 Nameservers

    - +

@@ -374,16 +356,16 @@ resolver .

- +

    1.4.2 Types of Zones

    - +

-As we stated previously, a zone is a point of delegation in the DNS tree. A zone consists of those contiguous parts of the domain tree for which a domain server has complete information and over which it has authority. It contains all domain names from a certain point downward in the domain tree except those which are delegated to other zones. A delegation point has one or more NS records in the parent zone, which should be matched by equivalent NS records at the root of the delegated zone (i.e., the "@" name in the zone file).

+As we stated previously, a zone is a point of delegation in the DNS tree. A zone consists of those contiguous parts of the domain tree for which a domain server has complete information and over which it has authority. It contains all domain names from a certain point downward in the domain tree except those which are delegated to other zones. A delegation point has one or more NS records in the parent zone, which should be matched by equivalent NS records at the root of the delegated zone.

@@ -417,11 +399,11 @@ subdomains

-Though BIND is a Domain Nameserver, it deals primarily in terms of zones. The primary and secondary declarations in the -named.conf - file specify zones, not domains. When you ask some other site if it is willing to be a secondary server for your +Though BIND is a Domain Nameserver, it deals primarily in terms of zones. The master and slave declarations in the +named.conf + file specify zones, not domains. When you ask some other site if it is willing to be a slave server for your domain -, you are actually asking for secondary service for some collection of zones.

+, you are actually asking for slave service for some collection of zones.

@@ -458,12 +440,12 @@ authoritative Adding a zone as a type master or type slave will tell the server to answer questions for the zone authoritatively. If the server is able to load the zone into memory without any errors it will set the AA bit when it replies to queries for the zone. See RFCs 1034 and 1035 for more information about the AA bit.

- +

    1.4.3 Servers

    - +

@@ -479,12 +461,12 @@ secondaries All servers keep data in their cache until the data expires, based on a Time To Live (TTL) field which is maintained for all resource records.

- +
    1.4.3.1 Master Server
    - +

@@ -493,12 +475,12 @@ primary master server is the ultimate source of information about a domain. The primary master is an authoritative server configured to be the source of zone transfer for one or more secondary servers. The primary master server obtains data for the zone from a file on disk.

- +
    1.4.3.2 Slave Server
    - +

@@ -509,12 +491,12 @@ secondary server , is an authoritative server that uses zone transfers from the primary master server to retrieve the zone data. Optionally, the slave server obtains zone data from a cache on disk. Slave servers provide necessary redundancy. All secondary/slave servers are named in the NS RRs for the zone.

- +
    1.4.3.3 Caching Only Server
    - +

@@ -523,12 +505,12 @@ caching only servers . This means that the server caches the information that it receives and uses it until the data expires. A caching only server is a server that is not authoritative for any zone. This server services queries and asks other servers, who have the authority, for the information it needs.

- +
    1.4.3.4 Forwarding Server
    - +

@@ -543,12 +525,12 @@ recursive queries There is no prohibition against declaring a server to be a forwarder even though it has master and/or slave zones as well; the effect will still be that anything in the local server's cache or zones will be answered, and anything else will be forwarded using the forwarders list.

- +
    1.4.3.5 Stealth Server
    - +

@@ -558,8 +540,9 @@ stealth server

-
-

Return to BINDv9 Administrator Reference Manual -

+
+

Return to BIND 9 Administrator Reference Manual table of contents.

+ + diff --git a/doc/arm/Bv9ARM.2.html b/doc/arm/Bv9ARM.2.html index 68f0970fea..a3ec8a7fe4 100644 --- a/doc/arm/Bv9ARM.2.html +++ b/doc/arm/Bv9ARM.2.html @@ -1,23 +1,4 @@ - - - - @@ -27,75 +8,75 @@

    - + Section 2. BIND Resource Requirements

    - + 2.1 Hardware requirements

- + DNS hardware requirements have traditionally been quite modest. For many installations, servers that have been pensioned off from active duty have performed admirably as DNS servers.

- -The DNSSEC and IPv6 features of BINDv9 may prove to be quite CPU intensive however, so organizations that make heavy use of these features may wish to consider larger systems for these applications. BINDv9 is now fully multithreaded, allowing full utilization of multiprocessor systems for installations that need it.

+ +The DNSSEC and IPv6 features of BIND 9 may prove to be quite CPU intensive however, so organizations that make heavy use of these features may wish to consider larger systems for these applications. BIND 9 is now fully multithreaded, allowing full utilization of multiprocessor systems for installations that need it.

    - + 2.2 CPU Requirements

- -CPU requirements for BINDv9 range from i486-class machines for serving of static zones without caching, to enterprise-class machines if you intend to process many dynamic updates and DNSSEC signed zones, serving many thousands of queries per second.

+ +CPU requirements for BIND 9 range from i486-class machines for serving of static zones without caching, to enterprise-class machines if you intend to process many dynamic updates and DNSSEC signed zones, serving many thousands of queries per second.

    - + 2.3 Memory Requirements

- -The memory of the server has to be large enough to fit the cache and zones loaded off disk. Future releases of BINDv9 will provide methods to limit the amount of memory used by the cache, at the expense of reducing cache hit rates and causing more DNS traffic. It is still good practice to have enough memory to load all zone and cache data into memory--unfortunately, the best way to determine this for a given installation is to watch the nameserver in operation. After a few weeks the server process should reach a relatively stable size where entries are expiring from the cache as fast as they are being inserted. Ideally, the resource limits should be set higher than this stable size.

+ +The memory of the server has to be large enough to fit the cache and zones loaded off disk. Future releases of BIND 9 will provide methods to limit the amount of memory used by the cache, at the expense of reducing cache hit rates and causing more DNS traffic. It is still good practice to have enough memory to load all zone and cache data into memory--unfortunately, the best way to determine this for a given installation is to watch the nameserver in operation. After a few weeks the server process should reach a relatively stable size where entries are expiring from the cache as fast as they are being inserted. Ideally, the resource limits should be set higher than this stable size.

    - + 2.4 Nameserver Intensive Environment Issues

- + For nameserver intensive environments, there are two alternative configurations that may be used. The first is where clients and any second-level internal nameservers query a main nameserver, which has enough memory to build a large cache. This approach minimizes the bandwidth used by external name lookups. The second alternative is to set up second-level internal nameservers to make queries independently. In this configuration, none of the individual machines needs to have as much memory or CPU power as in the first alternative, but this has the disadvantage of making many more external queries, as none of the nameservers share their cached data.

    - -2.5 Operating Systems Supported by the Internet Software Consortium

    + +2.5 Supported Operating Systems

- -ISC BINDv9 compiles and runs on the following operating systems:

+ +ISC BIND 9 compiles and runs on the following operating systems:

- + IBM AIX 4.3
Compaq Digital/Tru64 UNIX 4.0D
HP HP-UX 11
@@ -105,8 +86,9 @@ Sun Solaris 2.6, 7, 8 (beta)
FreeBSD 3.4-STABLE
NetBSD-current with "unproven" pthreads

-
-

Return to BINDv9 Administrator Reference Manual -

+
+

Return to BIND 9 Administrator Reference Manual table of contents.

+ + diff --git a/doc/arm/Bv9ARM.3.html b/doc/arm/Bv9ARM.3.html index af0dbf7b56..5e667f1135 100644 --- a/doc/arm/Bv9ARM.3.html +++ b/doc/arm/Bv9ARM.3.html @@ -1,128 +1,122 @@ - - - - Section 3. Nameserver Configuration - +

    Section 3. Nameserver Configuration

    - +

In this section we provide some suggested configurations along with guidelines for their use. We also address the topic of reasonable option setting.

- +

    3.1 - -Sample Configuration and Logging

    + +Sample Configurations +
+
+
    +

    + + +3.1.1 A Caching-only Nameserver

    +
+

+ + +The following sample configuration is appropriate for a caching-only name server for use by clients internal to a corporation. All queries from outside clients are refused.

-

-logging {
-       channel named_log {
-           file "logs/named.log";
-           print-time yes;
-           print-category yes;
-           print-severity yes;
-           severity info;
+
+
+// Two corporate subnets we wish to allow queries from.
+acl "corpnets" { 192.168.4.0/24; 192.168.7.0/24; };
+options {
+     directory "/etc/namedb";		// Working directory
+     pid-file "named.pid";		// Put pid file in working dir
+     allow-query { "corpnets "; };
 };
-       channel security_log {
-           file "logs/security.log" versions 7 ;
-           print-time yes;
-};
-       category default { named_log; default_debug; };
-       category security { security_log };
-};
-							// The two corporate subnets.
-							// Use real IP numbers
-							// here in the real world.
-acl corpnet { 192.168.4.0/24; 192.168.7.0/24; };
-							// The options statement.
-options {	
-   directory "/etc/namedb";				// Directory
-   pid-file "named.pid";				// Put .pid file in named directory.
-   check-names master fail;				// Fail on db errors in master zones.
-   check-names slave warn;				// Warn about db errors
-							// in slave zones.
-   check-names response warn;				// Warn about invalid responses
-   use-id-pool yes;					// Help prevent spoofing
-   host-statistics yes;					// Keep track of hosts/servers
-							// we've talked to.
-   listen-on { 192.168.7.20; };				// Listen on this address.
-   query-source address 192.168.7.20 port 53 ;
-							// Source queries from port 53
-							// to get past firewall.
-   allow-transfer { none; };				// Don't allow anyone to
-							// transfer zones.
-   allow-query { corpnet; };				// Allow only corpnets to query server.
-							// Helps prevent DoS, spoofing.
-   allow-recursion { corpnet; };			// Same, except this is for recursion.
-};
-
-

-

-include "keys.conf";					// Include a keys.conf with
-								// TSIG/DNSSEC keys.
-								// Shouldn't be readable to anyone
-								// except BIND user.
-zone "."{ type hint; file "local/named.root"; };
-								// root hints
-zone "0.0.127.IN-ADDR.ARPA" {
-

-

-        type master; file "local/localhost.db"; notify no;
-								// localhost
-};
-
zone "example.com" {			// Example zone for "example.com".
-type master;				// It's a master zone.
-file "m/example.com.db";		// The file is here.
-allow-query { any; };			// Allow anyone to query.
-allow-transfer { corpnet; };		// Only allow corp nets to transfer zone.
-};
+// Root server hints
+zone "." { type hint; file "root.hint"; };
+// Provide a reverse mapping for the loopback address 127.0.0.1
+zone "0.0.127.in-addr.arpa" {
+     type master;
+     file "localhost.rev";
+     notify no;
 
-

-zone "offsite.example.com" {		// Example zone for an off-site corp zone.
-type slave;					// It's a slave zone.
-masters { 192.168.4.12; };			// The master is at this address.
-file "s/offsite.example.com.db";		// The file is here.
-notify no;				// Don't worry about NOTIFYing.
-allow-query { any; };				// Allow anyone to query.
-};
+};
+
    +

    + + +3.1.2 An Authoritative-only Nameserver

    +
+

+ + +This sample configuration is for an authoritative-only server that is the master server for " +example.com +" and a slave for the subdomain " +eng.example.com +".

+
+options {
+     directory "/etc/namedb";		// Working directory
+     pid-file "named.pid";		// Put pid file in working dir
+     allow-query { any; };		// This is the default
+     recursion no;			// Do not provide recursive service
+};
+// Root server hints
+zone "." { type hint; file "root.hint"; }; 
+
+// Provide a reverse mapping for the loopback address 127.0.0.1
+     zone "0.0.127.in-addr.arpa" {
+     type master;
+     file "localhost.rev";
+     notify no;
+};
+// We are the master server for example.com
+zone "example.com" {
+     type master;
+     file "example.com.db";
+     // IP addresses of slave servers allowed to transfer example.com
+     allow-transfer {
+          192.168.4.14;
+          192.168.5.53;
+     };
+};
+
+// We are a slave server for eng.example.com
+zone "eng.example.com" {
+     type slave;
+     file "eng.example.com.bk";
+     // IP address of eng.example.com master server
+     masters { 192.168.4.12; };
+};
+
+ +
+
+
+

    -3.2 Load Balancing and Round Robin

    - +3.2 Load Balancing +

@@ -130,218 +124,242 @@ Primitive load balancing can be achieved in DNS using multiple A records for one

-For example, if you have three WWW servers with network addresses of 10.0.0.1, 10.0.0.2 and 10.0.0.3, a set of records like the following means that clients will connect to each machine one third of the time:

+For example, if you have three WWW servers with network addresses of 10.0.0.1, 10.0.0.2 and 10.0.0.3, a set of records such as the following means that clients will connect to each machine one third of the time:


  

- + + Name

- + + TTL

- + + CLASS

- + + TYPE

- + + Resource Record (RR) Data

- - -www + + + +www

- - -600 + + + +600

- - -IN + + + +IN

- - -A + + + +A

- - -10.0.0.1 + + + +10.0.0.1

- - - + + + +  

- - -600 + + + +600

- - -IN + + + +IN

- - -A + + + +A

- - -10.0.0.2 + + + +10.0.0.2

- - - + + + +  

- - -600 + + + +600

- - -IN + + + +IN

- - -A + + + +A

- - -10.0.0.3 + + + +10.0.0.3

- -When a resolver queries for these records, BIND will rotate them and respond to the query with the records in a different order. This is known as cyclic or round-robin ordering. In the example above, the first client will receive the records in the order 1, 2, 3; the second client will receive them in the order 2, 3, 1; and the third 3, 1, 2. Most clients will use the first record returned and discard the rest.

+ + +When a resolver queries for these records, BIND will rotate them and respond to the query with the records in a different order. In the example above, clients will randomly receive records in the order 1, 2, 3; 2, 3, 1; and 3, 1, 2. Most clients will use the first record returned and discard the rest.

- + + For more detail on ordering responses, check the rrset-order substatement in the options - statement in -RRset Ordering -.

+ statement under RRset Ordering. This substatement is not supported in BIND 9, and only the ordering scheme described above is available.

- +

    - -3.3 + + +3.3 + Notify

    - +

- -DNS Notify is a mechanism that allows master nameservers to notify their slave servers of changes to a zone's data and that a query should be initiated to discover the new data.

+ + +DNS Notify is a mechanism that allows master nameservers to notify their slave servers of changes to a zone's data. In response to a +NOTIFY + from a master server, the slave will check to see that its version of the zone is the current version and, if not, initiate a transfer.

- + DNS Notify is fully documented in RFC 1996. See also the description of the zone option also-notify - in -Zone Transfers + under Zone Transfers . More information about notify - can be found in Boolean Options + can be found under Boolean Options .

- +

    - + 3.4 Nameserver Operations

    - +
- +

    - + 3.4.1 Tools for Use With the Nameserver Daemon

    - +

- + There are several indispensable diagnostic, administrative and monitoring tools available to the system administrator for controlling and debugging the nameserver daemon. We describe several in this section

- +
    - + 3.4.1.1 Diagnostic Tools
    - +
- + dig

- + The domain information groper ( dig ) is a command line tool that can be used to gather information from the Domain Name System servers. Dig has two modes: simple interactive mode for a single query, and batch mode which executes a query for each in a list of several query lines. All query options are accessible from the command line.

@@ -349,30 +367,34 @@ dig
- + Usage
-
 
+
+
 dig [@server] domain [<query-type>] [<query-class>]
-[+<query-option>] [-<dig-option>] [%comment]

+     [+<query-option>] [-<dig-option>] [%comment]
+

- + The usual simple use of dig will take the form

-
 
-dig @server domain query-type query-class
+
+
+dig @server domain query-type query-class
+

- + For more information and a list of available commands and options, see the dig man page.

- + host

- + The @@ -384,19 +406,21 @@ utility provides a simple DNS lookup using a command-line interface for looking

- + Usage
-
 
-host [-l] [-v] [-w] [-r] [-d] [-t querytype] [-a] host [server]
-
+
+
+host [-aCdlrTwv] [-c class] [-N ndots] [-t type]
+     [-W timeout] [-R retries] hostname [server]
+
- + nslookup

- + nslookup is a program used to query Internet domain nameservers. @@ -406,55 +430,67 @@ nslookup

- + Usage
-
 
-nslookup [-option ...] [host-to-find | -[server]]
+
+
+nslookup [-option ...] [host-to-find | -[server]]
+

- -Interactive mode is entered when no arguments are given (the default nameserver will be used) or when the first argument is a hyphen (-) and the second argument is the host name or Internet address of a nameserver.

+ +Interactive mode is entered when no arguments are given (the default nameserver will be used) or when the first argument is a hyphen (`-') and the second argument is the host name or Internet address of a nameserver.

- + Non-interactive mode is used when the name or Internet address of the host to be looked up is given as the first argument. The optional second argument specifies the host name or address of a nameserver.

- + The options listed under the "set" command (see the nslookup man page for details) can be specified in the .nslookuprc file in the user's home directory if they are listed one per line. Options can also be specified on the command line if they precede the arguments and are prefixed with a hyphen. For example, to change the default query type to host information, and the initial time-out to 10 seconds, type:

-
 
-nslookup -query=hinfo -timeout=10
+
+
+nslookup -query=hinfo -timeout=10
+

- - + + For more information and a list of available commands and options, see the nslookup man page.

+

+ + +Due to its arcane user interface and frequently inconsistent behavior, we do not recommend the use of +nslookup +, and it is not installed by default when installing BIND 9. Use +dig + instead.

- +
    - - + + 3.4.1.2 Administrative Tools
    - +

- + Administrative tools play an integral part in the management of a server.

- + rndc

- + The remote name daemon control ( rndc ) program is a program that allows the system administrator to control the operation of a nameserver. If you run @@ -462,22 +498,24 @@ rndc without any options it will display a usage message.

- + Usage:

-
 
-rndc [-p port] [-m] server command [command ...]
-
+
+
+rndc [-p port] [-m] server command [command ...]
+

- + For more information and a list of available commands and options, see the rndc man page.

- +
+

Return to BIND 9 Administrator Reference Manual table of contents.

+ + diff --git a/doc/arm/Bv9ARM.4.html b/doc/arm/Bv9ARM.4.html index ccb0c4c80b..377b04e2c3 100644 --- a/doc/arm/Bv9ARM.4.html +++ b/doc/arm/Bv9ARM.4.html @@ -1,23 +1,4 @@ - - - - @@ -27,25 +8,25 @@

- + Section 4. Advanced Concepts

- + 4.1 - + Dynamic Update

- + Dynamic update is the term used for the ability under certain specified conditions to add, modify or delete records or RRsets in the master zone files. Dynamic update is fully described in RFC 2136.

- + Dynamic update is enabled on a zone-by-zone basis, by including an allow-update or @@ -55,41 +36,43 @@ zone statement.

- + Updating of secure zones (zones using DNSSEC) is modelled after the simple-secure-update - proposal, a work in progress in the DNS Extensions working group of the IETF. (See -http://www.ietf.org/html.charters/dnsext-charter.html + proposal, a work in progress in the DNS Extensions working group of the IETF. (See
+ +http://www.ietf.org/html.charters/dnsext-charter.html for information about the DNS Extensions working group.) SIG and NXT records affected by updates are automatically regenerated by the server using an online zone key. Update authorization is based on transaction signatures and an explicit server policy.

- + The zone files of dynamic zones must not be edited by hand. The zone file on disk at any given time may not contain the latest changes performed by dynamic update. The zone file is written to disk only periodically, and changes that have occurred since the zone file was last written to disk are stored only in the zone's journal ( .jnl -) file. BINDv9 currently does not update the zone file when it exits like BIND 8 does, so editing the zone file manually is unsafe even when the server has been shut down.

+) file. BIND 9 currently does not update the zone file when it exits as BIND 8 does, so editing the zone file manually is unsafe even when the server has been shut down.

- + 4.2 - + Incremental Zone Transfers (IXFR)

- -The incremental zone transfer (IXFR) protocol is a way for slave servers to transfer only changed data, instead of having to transfer the entire zone. The IXFR protocol is documented in RFC 1995. See the list of proposed standards in Appendix C, -Proposed Standards.

+ +The incremental zone transfer (IXFR) protocol is a way for slave servers to transfer only changed data, instead of having to transfer the entire zone. The IXFR protocol is documented in RFC 1995. See the list of proposed standards in Appendix C + +.

- -When acting as a master, BINDv9 supports IXFR for those zones where the necessary change history information is available. These include master zones maintained by dynamic update and slave zones whose data was obtained by IXFR, but not manually maintained master zones nor slave zones obtained by performing a full zone transfer (AXFR).

+ +When acting as a master, BIND 9 supports IXFR for those zones where the necessary change history information is available. These include master zones maintained by dynamic update and slave zones whose data was obtained by IXFR, but not manually maintained master zones nor slave zones obtained by performing a full zone transfer (AXFR).

- -When acting as a slave, BINDv9 will attempt to use IXFR unless it is explicitly disabled. For more information about disabling IXFR, see the description of the + +When acting as a slave, BIND 9 will attempt to use IXFR unless it is explicitly disabled. For more information about disabling IXFR, see the description of the request-ixfr clause of the server @@ -99,52 +82,50 @@ server

- + 4.3 Split DNS

- -Setting up different views, or visibility, of DNS space to internal, as opposed to external, resolvers is usually referred to as a + +Setting up different views, or visibility, of DNS space to internal and external resolvers is usually referred to as a Split DNS - or -Split Brain DNS setup. There are several reasons an organization would want to set up its DNS this way.

- + One common reason for setting up a DNS system this way is to hide "internal" DNS information from "external" clients on the Internet. There is some debate as to whether or not this is actually useful. Internal DNS information leaks out in many ways (via email headers, for example) and most savvy "attackers" can find the information they need using other means.

- -Another common reason for setting up a Split DNS system is to allow internal networks that are behind filters or RFC 1918 space (reserved IP space, as documented in RFC 1918) to resolve DNS on the Internet. Split DNS can also be used to allow mail from outside back in to the internal network.

+ +Another common reason for setting up a Split DNS system is to allow internal networks that are behind filters or in RFC 1918 space (reserved IP space, as documented in RFC 1918) to resolve DNS on the Internet. Split DNS can also be used to allow mail from outside back in to the internal network.

- + Here is an example of a split DNS setup:

- + Let's say a company named Example, Inc. (example.com) has several corporate sites that have an internal network with reserved Internet Protocol (IP) space and an external demilitarized zone (DMZ), or "outside" section of a network, that is available to the public.

- + Example, Inc. wants its internal clients to be able to resolve external hostnames and to exchange mail with people on the outside. The company also wants its internal resolvers to have access to certain internal-only zones that are not available at all outside of the internal network.

- + In order to accomplish this, the company will set up two sets of nameservers. One set will be on the inside network (in the reserved IP space) and the other set will be on bastion hosts, which are "proxy" hosts that can talk to both sides of its network, in the DMZ.

- + The internal servers will be configured to forward all queries, except queries for -site1.example +site1.internal , -site2.example +site2.internal , site1.example.com , and @@ -162,7 +143,7 @@ site2.internal .

- + To protect the site1.interna @@ -174,7 +155,7 @@ site2.internal domains, the internal nameservers must be configured to disallow all queries to these domains from any external hosts, including the bastion hosts.

- + The external servers, which are on the bastion hosts, will be configured to serve the "public" version of the site1 and @@ -190,43 +171,44 @@ b.mx.example.com ).

- + In addition, the public site1 and site2.example.com - zones should have special MX records that contain wildcard ('*') records pointing to the bastion hosts. This is needed because external mail servers do not have any other way of looking up how to deliver mail to those internal hosts. With the wildcard records, the mail will be delivered to the bastion host, which can then forward it on to internal hosts.

+ zones should have special MX records that contain wildcard (`*') records pointing to the bastion hosts. This is needed because external mail servers do not have any other way of looking up how to deliver mail to those internal hosts. With the wildcard records, the mail will be delivered to the bastion host, which can then forward it on to internal hosts.

- + Here's an example of a wildcard MX record:

-
 
-*   IN MX 10 external1.example.com.
-
+
+
+*   IN MX 10 external1.example.com.
+

- + Now that they accept mail on behalf of anything in the internal network, the bastion hosts will need to know how to deliver mail to internal hosts. In order for this to work properly, the resolvers on the bastion hosts will need to be configured to point to the internal nameservers for DNS resolution.

- + Queries for internal hostnames will be answered by the internal servers, and queries for external hostnames will be forwarded back out to the DNS servers on the bastion hosts.

- + In order for all this to work properly, internal clients will need to be configured to query only the internal nameservers for DNS queries. This could also be enforced via selective filtering on the network.

- + If everything has been set properly, Example, Inc. 's internal clients will now be able to:

  • - + Look up any hostnames in the site1 and @@ -234,7 +216,7 @@ site2.example.com zones.
  • - + Look up any hostnames in the site1.internal and @@ -242,21 +224,21 @@ site2.internal domains.
  • - + Look up any hostnames on the Internet.
  • - + Exchange mail with internal AND external people.

- + Hosts on the Internet will be able to:

  • - + Look up any hostnames in the site1 and @@ -264,7 +246,7 @@ site2.example.com zones.
  • - + Exchange mail with anyone in the site1 and @@ -273,115 +255,114 @@ site2.example.com

- -Here is an example configuration for the setup we just described above. Note that this is only configuration information; for information on how to configure your zone files, see -Sample Configuration and Logging + +Here is an example configuration for the setup we just described above. Note that this is only configuration information; for information on how to configure your zone files, see the Sample Configurations + .

Internal DNS server config:

-

-acl internals { 172.16.72.0/24; 192.168.1.0/24; };
-acl externals { bastion-ips-go-here; };
+
+
+
+acl internals { 172.16.72.0/24; 192.168.1.0/24; };
+acl externals { bastion-ips-go-here; };
 options {
     ...
     ...
     forward only;
-    forwarders { bastion-ips-go-here; };															// forward to external servers
-    allow-transfer { none; };															// sample allow-transfer (no one)
-    allow-query { internals; externals; };															// restrict query access
-    allow-recursion { internals; };															// restrict recursion
+    forwarders { bastion-ips-go-here; };	// forward to external servers
+    allow-transfer { none; };			// sample allow-transfer (no one)
+    allow-query { internal; externals; };	// restrict query access
+    allow-recursion { internals; };		// restrict recursion
     ...
     ...
-};
-

-

-zone "site1.example.com" { 															// sample slave zone
-  type master;
-  file "m/site1.example.com";
-  forwarders { }; 															// do normal iterative
-															// resolution (do not forward)
-  allow-query { internals; externals; };
-  allow-transfer { internals; };
-};
-

-

-zone "site2.example.com" {
-  type slave;
-  file "s/site2.example.com"
+};
+

+
+zone "site1.example.com" { 			// sample slave zone
+  type master;
+  file "m/site1.example.com";
+  forwarders { }; 				// do normal iterative
+						// resolution (do not forward)
+  allow-query { internals; externals; };
+  allow-transfer { internals; };
+  };
+

+
+zone "site2.example.com" {
+  type slave;
+  file "s/site2.example.com";
   masters { 172.16.72.3; };
   forwarders { };
-  allow-query { internals; externals; };
-  allow-transfer { internals; };
-};
-

-

-zone "site1.internal
-" {
-  type master;
-  file "m/site1.internal";
+  allow-query { internals; externals; };
+  allow-transfer { internals; };
+};
+

+
+zone "site1.internal" {
+  type master;
+  file "m/site1.internal";
   forwarders { };
-  allow-query { internals; };
-  allow-transfer { internals; }
-};
+  allow-query { internals; };
+  allow-transfer { internals; }
+};
 

-

-zone "site2.internal" {
-  type slave;
-  file "s/site2.internal";
+
+zone "site2.internal" {
+  type slave;
+  file "s/site2.internal";
   masters { 172.16.72.3; };
   forwarders { };
-  allow-query { internals };
-  allow-transfer { internals; }
-};
-

-

-
-
-External (bastion host) DNS server config:

-

-acl internals { 172.16.72.0/24; 192.168.1.0/24; };
-acl externals { bastion-ips-go-here; };
+  allow-query { internals };
+  allow-transfer { internals; }
+};
+

+External (bastion host) DNS server config:
+
+
+acl internals { 172.16.72.0/24; 192.168.1.0/24; };
+acl externals { 
+bastion-ips-go-here; };
 options {
   ...
   ...
-  allow-transfer { none; };															// sample allow-transfer (no one)
-  allow-query { internals; externals; };															// restrict query access
-  allow-recursion { internals; externals; };															// restrict recursion
+  allow-transfer { none; };							// sample allow-transfer (no one)
+  allow-query { internals; externals; };							// restrict query access
+  allow-recursion { internals; externals; };							// restrict recursion
   ...
   ...
-};
+};
 

-

-zone "site1.example.com" {															// sample slave zone
-  type master;
-  file "m/site1.foo.com";
-  allow-query { any; };
-  allow-transfer { internals; externals; };
-};
+
+zone "site1.example.com" { // sample slave zone
+  type master;
+  file "m/site1.foo.com";
+  allow-query { any; };
+  allow-transfer { internals; externals; };
+};
 

-

-zone "site2.example.com" {
-  type slave;
-  file "s/site2.foo.com";
-  masters { another_bastion_host_maybe; };
-  allow-query { any; };
-  allow-transfer { internals; externals; }
-};
-

-

-
-
-In the 
-resolv.conf
- (or equivalent) on the bastion host(s):

-

-search ...
+
+zone "site2.example.com" {
+  type slave;
+  file "s/site2.foo.com";
+  masters { another_bastion_host_maybe; };
+  allow-query { any; };
+  allow-transfer { internals; externals; }
+};
+

+
+In the resolv.conf (or equivalent) on the bastion host(s):
+
+
+
+search ...
 nameserver 172.16.72.2
 nameserver 172.16.72.3
-nameserver 172.16.72.4
+nameserver 172.16.72.4
 

+
@@ -399,15 +380,14 @@ This is a short guide to setting up Transaction SIGnatures (TSIG) based transact

-BIND primarily supports TSIG for server to server communication. This includes zone transfer, notify, and recursive query messages. The resolver bundled with BIND 8.2 has limited support for TSIG, but it is doubtful that support will be integrated into any client applications.

+BIND primarily supports TSIG for server to server communication. This includes zone transfer, notify, and recursive query messages. Resolvers based on newer versions of BIND 8 have limited support for TSIG.

-TSIG might be most useful for dynamic update. A primary server for a dynamic zone should use access control to control updates, but IP-based access control is insufficient. Key-based access control is far superior. See RFC 2845 in the -Proposed Standards -section of the Appendix. The +TSIG might be most useful for dynamic update. A primary server for a dynamic zone should use access control to control updates, but IP-based access control is insufficient. Key-based access control is far superior. See RFC 2845 in the Proposed Standards + section of the Appendix. The nsupdate - program that is shipped with BIND 8 supports TSIG via the " + program that is shipped with BIND 8 supports TSIG via the " -k " command line option.

@@ -420,7 +400,11 @@ nsupdate

-A shared secret is generated to be shared between host1 and host2. The key name is chosen to be "host1-host2.", which is arbitrary. The key name must be the same on both hosts.

+A shared secret is generated to be shared between +host1 + and +host2 +. An arbitrary key name is chosen: "host1-host2.". The key name must be the same on both hosts.

@@ -430,22 +414,30 @@ A shared secret is generated to be shared between host1 and host2. The key name

- + The following command will generate a 128 bit (16 byte) HMAC-MD5 key as described above. Longer keys are better, but shorter keys are easier to read. Note that the maximum key length is 512 bits; keys longer than that will be digested with MD5 to produce a 128 bit key.

-

-bin/dnssec/dnssec-keygen -a hmac-md5 -b 128 -n HOST host1-host2.
-
+
+
+dnssec-keygen -a hmac-md5 -b 128 -n HOST host1-host2.
+

- -The key is in the file "Khost1-host2.+157+00000.private". Nothing actually uses this file, but the base-64 encoded string following "Key:" can be extracted:

-

-   La/E5CjG9O+os1jq0a2jdA==
-
+ +The key is in the file +Khost1-host2.+157+00000.private +. Nothing directly uses this file, but the base-64 encoded string following " +Key +:" can be extracted from the file and used as a shared secret:

+
+
+Key: La/E5CjG9O+os1jq0a2jdA==
+

-This string represents a shared secret.

+The string " +La/E5CjG9O+os1jq0a2jdA== +" can be used as the shared secret.

@@ -487,28 +479,29 @@ This is beyond the scope of DNS. A secure transport mechanism should be used. Th

- + Imagine host1 and host 2 - are both servers. The following is added to each server's -named.conf + are both servers. The following is added to each server's +named.conf file:

-

-key 
-host1-host2. {
-  algorithm hmac-md5;
-  secret "La/E5CjG9O+os1jq0a2jdA==";
-};
+
+
+key host1-host2. {
+  algorithm hmac-md5;
+  secret "La/E5CjG9O+os1jq0a2jdA==";
+};
 

+
 

 
 
-The algorithm, hmac-md5, is the only one supported by BIND. The secret is the one generated above. Since this is a secret, it is recommended that either 
-named.conf
- be non-world readable, or the key directive be added to a non-world readable file that is included by 
-named.conf
+The algorithm, hmac-md5, is the only one supported by BIND. The secret is the one generated above. Since this is a secret, it is recommended that either 
+named.conf
+ be non-world readable, or the key directive be added to a non-world readable file that is included by 
+named.conf
 .

 

 
@@ -525,19 +518,19 @@ At this point, the key is recognized. This means that if the server receives a m
 

 
 
-Since keys are shared between two hosts only, the server must be told when keys are to be used. The following is added to the 
-named.conf
+Since keys are shared between two hosts only, the server must be told when keys are to be used. The following is added to the 
+named.conf
  file for 
 host1
 , if the IP address of 
 host2
  is 10.1.2.3:

-

-server 
-10.1.2.3 {
-  keys { host1-host2. ;};
-};
-

+
+
+server 10.1.2.3 {
+  keys { host1-host2. ;};
+};
+

 

 
 
@@ -545,11 +538,23 @@ Multiple keys may be present, but only the first is used. This directive does no
 

 
 
-If host1 sends a message that is a response to that address, the message will be signed with the specified key. host1 will expect any responses to signed messages to be signed with the same key.

+If 
+host1
+ sends a message that is a response to that address, the message will be signed with the specified key. 
+host1
+ will expect any responses to signed messages to be signed with the same key.

 

 
 
-A similar statement must be present in host2's configuration file (with host1's address) for host2 to sign non-response messages to host1.

+A similar statement must be present in 
+host2
+'s configuration file (with 
+host1
+'s address) for 
+host2
+ to sign non-response messages to 
+host1
+.
@@ -571,20 +576,28 @@ key host1-host2. An example of an allow-update directive would be:

-

-allow-update { key host1-host2. ;};
-
+
+
+allow-update { key host1-host2. ;};
+

- + This allows dynamic updates to succeed only if the request was signed by a key named " host1-host2. ".

+

+ + +The more powerful +update-policy + statement is described Dynamic Update Policies +.

- + 4.4.6 Errors

@@ -637,86 +650,90 @@ TKEY

- - -4.6 - + + +4.6 SIG(0)

+ +

+ + +BIND 9 partially supports DNSSEC SIG(0) transaction signatures as specified in RFC 2535. SIG(0) uses public/private keys to authenticate messages. Access control is performed in the same manner as TSIG keys; privileges can be granted or denied based on the key name.

+

+ + +When a SIG(0) signed message is received, it will only be verified if the key is known and trusted by the server; the server will not attempt to locate and/or validate the key.

+

+ + +BIND 9 does not ship with any tools that generate SIG(0) signed messages.

+
+
+ +

+ + +4.7 + DNSSEC

- + Cryptographic authentication of DNS information is possible through the DNS Security ( DNSSEC -) extension, defined in RFC 2535. This section describes the creation and use of DNSSEC signed zones.

+) extensions, defined in RFC 2535. This section describes the creation and use of DNSSEC signed zones.

- -In order to set up a DNSSEC secure zone, there are a series of steps which must be followed. BINDv9 ships with several tools that are used in this process, which are explained in more detail below. In all cases, the " + +In order to set up a DNSSEC secure zone, there are a series of steps which must be followed. BIND 9 ships with several tools that are used in this process, which are explained in more detail below. In all cases, the " -h " option prints a full list of parameters.

- + There must also be communication with the administrators of the parent and/or child zone to transmit keys and signatures. A zone's security status must be indicated by the parent zone for a DNSSEC capable resolver to trust its data.

- + For other servers to trust data in this zone, they must either be statically configured with this zone's zone key or the zone key of another zone above this one in the DNS tree.

- -4.6.1 Generating Keys

+ +4.7.1 Generating Keys

- + The dnssec-keygen program is used to generate keys.

- + A secure zone must contain one or more zone keys. The zone keys will sign all other records in the zone, as well as the zone keys of any secure delegated zones. Zone keys must have the same name as the zone, a name type of ZONE , and must be usable for authentication. It is recommended that zone keys be mandatory to implement a cryptographic algorithm; currently the only key mandatory to implement an algorithm is DSA.

- + The following command will generate a 768 bit DSA key for the child.example zone:

-

- - - -dnssec-keygen - --a - -DSA - --b - -768 - --n - -ZONE - -child.example -.

+ +
+dnssec-keygen -a DSA -b 768 -n ZONE child.example.
+

- + Two output files will be produced: Kchild.example.+003+12345.key and Kchild.example.+003+12345.private (where 12345 is an example of a key identifier). The key file names contain the key name ( -child.example +child.example. ), algorithm (3 is DSA, 1 is RSA, etc.), and the key identifier (12345 in this case). The private key (in the .private file) is used to generate signatures, and the public key (in the @@ -724,67 +741,53 @@ child.example file) is used for signature verification.

- -To generate another key with the same properties, repeat the above command.

+ +To generate another key with the same properties (but with a different key identifier), repeat the above command.

- + The public keys should be inserted into the zone file with $INCLUDE - statements.

+ statements, including the +.key +files.

- -4.6.2 Creating a Keyset

+ +4.7.2 Creating a Keyset

- + The dnssec-makekeyset program is used to create a key set from one or more keys.

- + Once the zone keys have been generated, a key set must be built for transmission to the administrator of the parent zone, so that the parent zone can sign the keys with its own zone key and correctly indicate the security status of this zone. When building a key set, the list of keys to be included and the TTL of the set must be specified, and the desired signature validity period of the parent's signature may also be specified.

- + The list of keys to be inserted into the key set may also included non-zone keys present at the apex. dnssec-makekeyset may also be used at non-apex names.

- + The following command generates a key set containing the above key and another key similarly generated, with a TTL of 3600 and a signature validity period of 10 days starting from now.

-

- - - -dnssec-makekeyset - --t - -3600 - --s - -now - --e - -now+864000 - -Kchild.example.+003+12345 - -Kchild.example.+003+23456 -

+ +
+dnssec-makekeyset -t 3600 -s now -e now+864000 Kchild.example.+003+12345 
+Kchild.example.+003+23456
+
+

- + One output file is produced: child.example.keyset . This file should be transmitted to the parent to be signed. It includes the keys, as well as signatures over the key set generated by the zone keys themselves, which are used to prove ownership of the private keys and encode the desired validity period.

@@ -793,18 +796,18 @@ child.example.keyset

- -4.6.3 Signing the Child's Keyset

+ +4.7.3 Signing the Child's Keyset

- + The dnssec-signkey program is used to sign one child's keyset.

- + If the child.example zone has any delegations which are secure, for example, @@ -814,25 +817,17 @@ child.example administrator should receive keyset files for each secure subzone. These keys must be signed by this zone's zone keys.

- + The following command signs the child's key set with the zone keys:

-

- - - -dnssec-signkey - -grand.child.example.keyset - -Kchild.example.+003+12345 - - - -Kchild.example.+003+23456 -

+ +
+dnssec-signkey grand.child.example.keyset Kchild.example.+003+12345 
+Kchild.example.+003+23456
+
+

- + One output file is produced: grand.child.example.signedkey . This file should be both transmitted back to the child and retained. It includes all keys (the child's keys) from the keyset file and signatures generated by this zone's zone keys.

@@ -841,18 +836,18 @@ grand.child.example.signedkey

- -4.6.4 Signing the Zone

+ +4.7.4 Signing the Zone

- + The dnssec-signzone program is used to sign a zone.

- + Any signedkey files corresponding to secure subzones should be present, as well as a @@ -864,43 +859,37 @@ SIG records for the zone, as well as incorporate the zone key signature from the parent and indicate the security status at all delegation points.

- + The following command signs the zone, assuming it is in a file called zone.child.example . By default, all zone keys which have an available private key are used to generate signatures.

-

- - - -dnssec-signzone - --o - -child.example zone.child.example -

+ +
+dnssec-signzone -o child.example zone.child.example
+

- + One output file is produced: zone.child.example.signed -. This file should be referenced by -named.conf +. This file should be referenced by +named.conf as the input file for the zone.

- -4.6.5 Configuring Servers

+ +4.7.5 Configuring Servers

- -Unlike in BIND 8, data is not verified on load in BINDv9, so zone keys for authoritative zones do not need to be specified in the configuration file.

+ +Unlike in BIND 8, data is not verified on load in BIND 9, so zone keys for authoritative zones do not need to be specified in the configuration file.

- + The public key for any security root must be present in the configuration file's
trusted-keys @@ -910,749 +899,208 @@ trusted-keys

- - -4.7 IPv6

+ + +4.8 IPv6 Support in BIND 9 -
- -

- - -4.7.1 IPv6 addresses (A6)

- -

- - -IPv6 addresses are 128-bit identifiers for interfaces and sets of interfaces which were introduced in the DNS to facilitate scalable Internet routing. There are three types of addresses: -Unicast -, an identifier for a single interface; -Anycast -, an identifier for a set of interfaces; and -Multicast -, an identifier for a set of interfaces. Here we describe the global Unicast address scheme. For more information, see RFC 2374.

-

- - -The aggregatable global Unicast address format is as follows:

-

- - - 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - -3 - - - - -13 - - - - -8 - - - - -24 - - - - -16 - - - - -64 bits -
- - - -FP - - - - -TLA ID - - - - -RES - - - - -NLA ID - - - - -SLA ID - - - - -Interface ID -
- - - -<------ Public Topology ------> - - - - -  - - - - -  -
- - - -  - - - - -  - - - - -  - - - - -  - - - - -<-Site Topology-> - - - - -  -
- - - -  - - - - -  - - - - -  - - - - -  - - - - -  - - - - -<------ Interface Identifier ------> -
-

- - -Where

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - -FP

-		 -

- - -=

-		 -

- - -Format Prefix (001)

-
-

- - -TLA ID

-		 -

- - -=

-		 -

- - -Top-Level Aggregation Identifier

-
-

- - -RES

-		 -

- - -=

-		 -

- - -Reserved for future use

-
-

- - -NLA ID

-		 -

- - -=

-		 -

- - -Next-Level Aggregation Identifier

-
-

- - -SLA ID

-		 -

- - -=

-		 -

- - -Site-Level Aggregation Identifier

-
-

- - -INTERFACE ID

-		 -

- - -=

-		 -

- - -Interface Identifier

-
-

- - -The -Public Topology - is provided by the upstream provider or ISP, and (roughly) corresponds to the IPv4 -network - section of the address range. The -Site Topology - is where you can subnet this space, much like subnetting an IPv4 class A or B network into class Cs. The -Interface Identifier - is the address of an individual interface on a given network. (With IPv6, addresses belong to interfaces rather than machines.)

-

- - -The subnetting capability of IPv6 is much more flexible than that of IPv4: subnetting can now be carried out on bit boundaries, in much the same way as Classless InterDomain Routing (CIDR).

-

- - -The internal structure of the Public Topology for an A6 global unicast address consists of:

-

- - - 

- - - - - - - - - - - - - -
-

- - -3

-		 -

- - -13

-		 -

- - -8

-		 -

- - -24

-
-

- - -FP

-		 -

- - -TLA ID

-		 -

- - -RES

-		 -

- - -NLA ID

-
-

- - -A 3 bit FP (Format Prefix) of 001 indicates this is a global Unicast address. FP lengths for other types of addresses may vary.

-

- - -13 TLA (Top Level Aggregator) bits give the prefix of your top-level IP backbone carrier.

-

- - -8 Reserved bits

-

- - -24 bits for Next Level Aggregators. This allows organizations with a TLA to hand out portions of their IP space to client organizations, so that the client can then split up the network further by filling in more NLA bits, and hand out IPv6 prefixes to their clients, and so forth.

-

- - -There is no particular structure for the Site topology section. Organizations can allocate these bits in any way they desire, in the same way as they would subnet an IPv4 class A (8-bit prefix) network.

-

- - -The Interface Identifier must be unique on that network. On ethernet networks, one way to ensure this is to set the address to the first three bytes of the hardware address, "FFFE", then the last three bytes of the hardware address. The lowest significant bit of the first byte should then be complemented. Addresses are written as 32-bit blocks separated with a colon, and leading zeros of a block may be omitted, for example:

-
 
-3ffe:8050:201:9:a00:20ff:fe81:2b32
-
-

- - -IPv6 address specifications are likely to contain long strings of zeros, so the architects have included a shorthand for specifying them. The double colon ('::') indicates the longest possible string of zeros that can fit, and can be used only once in an address.

-
-
- -

- - -4.7.2 Name to Address Lookup

- -

- - -Forward name lookups (host name to IP address) under IPv6 do not necessarily return the complete IPv6 address of the host. Because the provider-assigned prefix may change, the A6 record can simply specify the locally assigned portion of the name, and refer to the provider for the remainder.

-

- - -This is an example of a complete IPv6 A6 record that provides the full 128 bit address:

- - - - - - - - - - - - - - - - - - -
-

- - -$ORIGIN example.com.

-
-

- - -; NAME

-		 -

- - -TTL TYPE

-		 -

- - -BITS IN REFERRAL

-		 -

- - -ADDRESS

-		 -

- - -REFERRAL

-
-

- - -host.example.com.

-		 -

- - -1h IN A6

-		 -

- - -0

-		 -

- - -3ffe:8050:201:9:a00:20ff:fe81:2b32

-		 -

- - -.

-
-

- - -Note that the number preceding the address is the number of bits to be provided via the referral. This is probably the easiest way to roll out an IPv6 installation, though you may wish to provide a reference to your provider assigned prefix:

- - - - - - - - - - - - - - - - - - -
-

- - -$ORIGIN example.com.

-
-

- - -; NAME

-		 -

- - -TTL TYPE

-		 -

- - -BITS IN REFERRAL

-		 -

- - -ADDRESS

-		 -

- - -REFERRAL

-
-

- - -host.example.com.

-		 -

- - -1h IN A6

-		 -

- - -48

-		 -

- - -::9:a00:20ff:fe81:2b32

-		 -

- - -prefix.example2.com.

-
-

- - -Then, in example2.com's zone:

- - - - - - - - - - - - - - - - - - -
-

- - -$ORIGIN example.com.

-
-

- - -; NAME

-		 -

- - -TTL TYPE

-		 -

- - -BITS IN REFERRAL

-		 -

- - -ADDRESS

-		 -

- - -REFERRAL

-
-

- - -prefix.example2.com.

-		 -

- - -1h IN A6

-		 -

- - -0

-		 -

- - -3ffe:8050:201::

-		 -

- - -.

-
-

- - -The referral where there are no more bits is to ".", the root zone. Be warned that excessive use of this chaining can lead to extremely poor name resolution for people trying to access your hosts.

-
-
- -

- - -4.7.3 Address to Name Lookup

- -

- - -Reverse IPv6 addresses may appear as one or more hex strings, known as "bitstring labels," each followed by a number of valid bits. A full 128 bits may be specified at the ip6.int top level, or more likely, the provider will delegate you a smaller chunk of addresses for which you will need to supply reverse DNS.

-

- - -The address can be split up along arbitrary boundaries, and is written with hex numbers in forward order, rather than in reverse order as IPv4 PTR records are written. The sections between dot separators are reversed as usual. If the number of valid bits in the hex string is less than the string specifies, it is the -first N bits - that are counted. Thus, \[x2/3] gives a bit pattern of 0010, the first three bits of which, 001, are valid.

-

- - -The address above, then, is:

-

- - - -\[x3FFE8050020100090A0020FFFE812B32/128].ip6.int. - (not divided)

-

- - - -\[x00090A0020FFFE812B32/80].\[xFFF402801008/45].\[x2/3].ip6.int. - (divided into FP, TLA/RES/NLA, and local)

-

- - - -\[x00090A0020FFFE812B32/80].\[x80500201/32].\[xFFF0/13].\[x2/3].ip6.int. - (divided into FP, TLA, RES/NLA, and local)

-

- - -These strings are all equivalent. The combined TLA/RES/NLA in the second example bears no resemblance to any string in the address because it is offset by three bits.

-
+

+ + +BIND 9 fully supports all currently defined forms of IPv6 name to address and address to name lookups. It will also use IPv6 addresses to make queries when running on an IPv6 capable system.

+

+ + +For forward lookups, BIND 9 supports both A6 and AAAA records. The of AAAA records is deprecated, but it is still useful for hosts to have both AAAA and A6 records to maintain backward compatibility with installations where AAAA records are still used. In fact, the stub resolvers currently shipped with most operating system support only AAAA lookups, because following A6 chains is much harder than doing A or AAAA lookups.

+

+ + +For IPv6 reverse lookups, BIND 9 supports the new "bitstring" format used in the +ip6.arpa + domain, as well as the older, deprecated "nibble" format used in the +ip6.int + domain.

+

+ + +BIND 9 includes a new lightweight resolver library and resolver daemon which new applications may choose to use to avoid the complexities of A6 chain following and bitstring labels. See +The BIND 9 Lightweight Resolver + for more information.

- -4.7.4 Using DNAME for Delegation of IPv6 Reverse Addresses

+ +4.8.1 Address Lookups Using AAAA Records + +

+ + +The AAAA record is a parallel to the IPv4 A record. It specifies the entire address in a single record. For example,

+
+
+$ORIGIN example.com.
+host	1h		IN	AAAA	3ffe:8050:201:1860:42::1
+
+

+ + +While their use is deprecated, they are useful to support older IPv6 applications. They should not be added where they are not absolutely necessary.

+
+
+ +

+ + +4.8.2 Address Lookups Using A6 Records

+ +

+ + +The A6 record is more flexible than the AAAA record, and is therefore more complicated. The A6 record can be used to form a chain of A6 records, each specifying part of the IPv6 address. It can also be used to specify the entire record as well. For example, this record supplies the same data as the AAAA record in the previous example:

+ +
+$ORIGIN example.com.
+host	1h		IN	A6	0	3ffe:8050:201:1860:42::1
+
+ +
+ +
+ + +4.8.2.1 A6 Chains
+ +

+ + +A6 records are designed to allow network renumbering. This works when an A6 record only specifies the part of the address space the domain owner controls. For example, a host may be at a company named "company." It has two ISPs which provide IPv6 address space for it. These two ISPs fully specify the IPv6 prefix they supply.

+

+ + +In the company's address space:

+ +
+$ORIGIN	example.com.
+host	1h	IN	A6	64	0:0:0:0:42::1	company.example1.net.
+host	1h	IN	A6	64	0:0:0:0:42::1	company.example2.net.
+
+ +

+ + +ISP1 will use:

+
+
+$ORIGIN example1.net.
+company		1h		IN		A6	0	3ffe:8050:201:1860::
+
+

+ + +ISP2 will use:

+
+
+$ORIGIN example2.net.
+company		1h		IN		A6	0	1234:5678:90ab:fffa::
+
+

+ + +When +host.example.com + is looked up, the resolver (in the resolver daemon or caching name server) will find two partial A6 records, and will use the additional name to find the remainder of the data.

+
+
+ +
+ + +4.8.2.2 A6 Records for DNS Servers
+ +

+ + +When an A6 record specifies the address of a name server, it should use the full address rather than specifying a partial address. For example:

+ +
+$ORIGIN example.com.
+@		4h	IN	NS	ns0
+		4h	IN	NS	ns1
+
+ns0		4h	IN	A6	0		3ffe:8050:201:1860:42::1
+ns1		4h	IN	A	192.168.42.1
+
+ +

+ + +It is recommended that IPv4-in-IPv6 mapped addresses not be used. If a host has an IPv4 address, use an A record, not an A6, with +::ffff:192.168.42.1 + as the address.

+
+
+
+ +

+ + +4.8.3 Address to Name Lookups Using Nibble Format

+ +

+ + +While the use of nibble format to look up names is deprecated, it is supported for backwards compatiblity with existing IPv6 applications.

+

+ + +When looking up an address in nibble format, the address components are simply reversed, just as in IPv4, and +ip6.int. + is appended to the resulting name. For example, the following would provide reverse name lookup for a host with address +3ffe:8050:201:1860:42::1 +.

+ + +
+$ORIGIN 0.6.8.1.1.0.2.0.0.5.0.8.e.f.f.3.ip6.int.
+1.0.0.0.0.0.0.0.0.0.0.0.2.4.0.0	4h										IN	PTR	host.example.com.
+
+
+
+ +

+ + +4.8.4 Address to Name Lookups Using Bitstring Format

+ +

+ + +Bitstring labels can start and end on any bit boundary, rather than on a multiple of 4 bits as in the nibble format. They also use +ip6.arpa + rather than +ip6.int +.

+

+ + +To replicate the previous example using bitstrings:

+ +
+$ORIGIN \[x3ffe805002011860/64].ip6.arpa.
+\[x0042000000000001/64]											4h		IN		PTR		host.example.com.
+
+ +
+
+ +

+ + +4.8.5 Using DNAME for Delegation of IPv6 Reverse Addresses

- + Delegation of reverse addresses is done through the new DNAME RR. In the example above, where \[x2/3].ip6.int. needs to delegate @@ -1666,44 +1114,50 @@ example2.com ), the domain administrator would insert a line similar to the following in the \[x2/3].ip6.int. zone:

-
 
-$ORIGIN \[x2/3].ip6.int.
-\[xFFF0/13] 1h IN DNAME ip6.example2.com.
+
+
+$ORIGIN \[x2/3].ip6.int.
+\[xFFF0/13] 1h IN DNAME ip6.example2.com.
 

+
 

 
- 
+
 
 example2.com
  would then place into the 
 ip6 
 zone:

-
 
-$ORIGIN ip6.example.com.
-\[x80500201/32] 1h IN DNAME ip6.example.com.
+
+
+$ORIGIN ip6.example.com.
+\[x80500201/32] 1h IN DNAME ip6.example.com.
 

+
 

 
- 
+
 Finally, 
 example.com 
 needs to include in the 
 ip6.example.com
  zone:

-
 
-$ORIGIN ip6.example.com.
-\[x00090A0020FFFE812B32/80] 1h IN PTR host.example.com.
+
+
+$ORIGIN ip6.example.com.
+\[x00090A0020FFFE812B32/80] 1h IN PTR host.example.com.
 

+
 

 
- 
+
 We suggest that the top of your administrative control (
 example.com
 , in this case) provide all the bits required for reverse and forward resolution to allow name resolution even if the network is disconnected from the Internet. This will also allow operation with DNSSEC if you set up a false trusted server for "." containing only  delegations for your forward and reverse zones directly to the top of your administrative control. This should be signed with a key trusted by all of your clients, equivalent to the real key for ".".
- +
+

Return to BIND 9 Administrator Reference Manual table of contents.

+ diff --git a/doc/arm/Bv9ARM.5.html b/doc/arm/Bv9ARM.5.html index 7588106507..8e4bfef408 100644 --- a/doc/arm/Bv9ARM.5.html +++ b/doc/arm/Bv9ARM.5.html @@ -1,6340 +1,76 @@ - - - - - Section 5. BINDv9 Configuration Reference + Section 5. The BIND 9 Lightweight Resolver - +

    - - -Section 5. BINDv9 Configuration Reference

    - -

    - - -BINDv9 configuration is broadly similar to BIND 8.x; however, there are a few new areas of configuration, such as views. BIND 8.x configuration files should work with few alterations in BINDv9, although more complex configurations should be reviewed to check if they can be more efficiently implemented using the new features found in BINDv9.

    -

    - - -BIND 4.9.x configuration files can be converted to the new format by using the Perl script -src/bin/named/named-bootconf.pl - from the BIND 8 release kit.

    + + +Section 5. + +The BIND 9 Lightweight Resolver +
- +

    - - -5.1 Configuration file elements

    - -

    - - -Following is a list of elements used throughout the BIND configuration file documentation:

    -

    - - - 

    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    -
    - - - -acl_name -
    -    		 -

    - - -The name of an -address_match_list - as defined by the -acl - statement.

    -
    -
    - - - -address_match_list -
    -    		 -

    - - -A list of one or more -ip_addr - -, - -ip_prefix - -, - -key_id - -, -or -acl_name - elements, as described in -Address Match Lists -.

    -
    -
    - - - -domain_name -
    -    		 -

    - - -A quoted string which will be used as a DNS name, for example " -my.test.domain -".

    -
    -
    - - - -dotted_decimal -
    -    		 -

    - - -One or more integers valued 0 through 255 separated only by dots ('.'), such as -123 -, -45.67 - or -89.123.45.67 -.

    -
    -
    - - - -ip4_addr -
    -    		 -

    - - -An IPv4 address with exactly four elements in -dotted_decimal - notation.

    -
    -
    - - - -ip6_addr -
    -    		 -

    - - -An IPv6 address, like -fe80::200:f8ff:fe01:9742 -.

    -
    -
    - - - -ip_addr -
    -    		 -

    - - -An -ip4_addr - or - - -ip6_addr -.

    -
    -
    - - - -ip_port -
    -    		 -

    - - -An IP port -number -. -number - is limited to 0 through 65535, with values below 1024 typically restricted to root-owned processes. In some cases an asterisk ('*') character can be used as a placeholder to select a random high-numbered port.

    -
    -
    - - - -ip_prefix -
    -    		 -

    - - -An IP network specified as an -ip_addr -, followed by a slash ('/') and then the number of bits in the netmask. For example, -127/8 - is the network -127.0.0.0 - with netmask -255.0.0.0 - and -1.2.3.0/28 - is network -1.2.3.0 - with netmask -255.255.255.240 -.

    -
    -
    - - - -key_name -
    -    		 -

    - - -A -domain_name - representing the name of a shared key, to be used for transaction security.

    -
    -
    - - - -number -
    -    		 -

    - - -A non-negative integer with an entire range limited by the range of a C language signed integer (2,147,483,647 on a machine with 32 bit integers). Its acceptable value might further be limited by the context in which it is used.

    -
    -
    - - - -path_name -
    -    		 -

    - - -A quoted string which will be used as a pathname, such as -" - -zones/master/my.test.domain - -" -.

    -
    -
    - - - -size_spec -
    -    		 -

    - - -A number, the word -unlimited -, or the word -default -.

    -

    - - -The maximum value of -size_spec - is that of unsigned long integers on the machine. An -unlimited - -size_spec - requests unlimited use, or the maximum available amount. A -default size_spec - uses the limit that was in force when the server was started.

    -

    - - -A -number - can optionally be followed by a scaling factor: -K - or -k - - -for kilobytes, -M - or -m - for megabytes, and -G - or -g - for gigabytes, which scale by 1024, 1024*1024, and 1024*1024*1024 respectively.

    -

    - - -Integer storage overflow is currently silently ignored during conversion of scaled values, resulting in values less than intended, possibly even negative. Using -unlimited - is the best way to safely set a really large number.

    -
    -
    - - - -yes_or_no -
    -    		 -

    - - -Either -yes - or -no -. The words -true - and -false - are also accepted, as are the numbers -1 - and -0 -.

    -
    -
    - -

    - - -5.1.1 - -Address Match Lists

    - -
    - -
    - + -5.1.1.1 Syntax
    - -
    
-address_match_list = address_match_list_element ;
-  [ address_match_list_element; ... ]
-address_match_list_element = [ ! ] (ip_address [/length] |
-  keykey_id | acl_name | { address_match_list } )
    -
    -
    - -
    - - -5.1.1.2 Definition and Usage
    - -

    - - -Address match lists are primarily used to determine access control for various server operations. They are also used to define priorities for querying other nameservers and to set the addresses on which -named - will listen for queries. The elements which constitute an address match list can be any of the following:

    - -
      -
    • an IP address (IPv4 or IPv6) - -
    • an IP prefix (in the '/'-notation) - -
    • a key ID, as defined by the key statement - -
    • the name of an address match list previously defined with the acl statement - -
    • a nested address match list enclosed in braces -
    - -

    - - -Elements can be negated with a leading exclamation mark ('!') and the match list names "any," "none," "localhost" and "localnets" are predefined. More information on those names can be found in the description of the acl statement.

    -

    - - -The addition of the key clause made the name of this syntactic element something of a misnomer, since security keys can be used to validate access without regard to a host or network address. Nonetheless, the term "address match list" is still used throughout the documentation.

    -

    - - -When a given IP address or prefix is compared to an address match list, the list is traversed in order until an element matches. The interpretation of a match depends on whether the list is being used for access control, defining listen-on ports, or as a topology, and whether the element was negated.

    -

    - - -When used as an access control list, a non-negated match allows access and a negated match denies access. If there is no match, access is denied. The clauses allow-query, allow-transfer, allow-update and blackhole all use address match lists like this. Similarly, the listen-on option will cause the server to not accept queries on any of the machine's addresses which do not match the list.

    -

    - - -When used with the topology clause, a non-negated match returns a distance based on its position on the list (the closer the match is to the start of the list, the shorter the distance is between it and the server). A negated match will be assigned the maximum distance from the server. If there is no match, the address will get a distance which is further than any non-negated list element, and closer than any negated element.

    -

    - - -Because of the first-match aspect of the algorithm, an element that defines a subset of another element in the list should come before the broader element, regardless of whether either is negated. For example, in
    - -1.2.3/24; ! 1.2.3.13; - the 1.2.3.13 element is completely useless because the algorithm will match any lookup for 1.2.3.13 to the 1.2.3/24 element. Using -! 1.2.3.13; 1.2.3/24 - fixes that problem by having 1.2.3.13 blocked by the negation but all other 1.2.3.* hosts fall through.

    -
    -
    -
-
- -

- - -5.1.2 Comment Syntax

- +5.1 The Lightweight Resolver Library +

- - -The BINDv9 comment syntax allows for comments to appear anywhere that white space may appear in a BIND configuration file. To appeal to programmers of all kinds, they can be written in C, C++, or shell/perl constructs.

-
- -
- - -5.1.2.1 Syntax
- -

- - -/* This is a BIND comment as in C */
-// This is a BIND comment as in C++
-# This is a BIND comment as in common UNIX shells and perl

+ + +Traditionally applications have been linked with a stub resolver library that sends recursive DNS queries to a local caching name server.

+

+ + +IPv6 introduces new complexity into the resolution process, such as following A6 chains and DNAME records, and simultaneous lookup of IPv4 and IPv6 addresses. These are hard or impossible to implement in a traditional stub resolver.

+

+ + +Instead, BIND 9 provides resolution services to local clients using a combination of a lightweight resolver library and a resolver daemon process running on the local host. These communicate using a simple UDP-based protocol, the "lightweight resolver protocol" that is distinct from and simpler than the full DNS protocol.

- -
- - -5.1.2.2 Definition and Usage
- -

- - -Comments may appear anywhere that whitespace may appear in a BIND configuration file.

-

- - -C-style comments start with the two characters /* (slash, star) and end with */ (star, slash). Because they are completely delimited with these characters, they can be used to comment only a portion of a line or to span multiple lines.

-

- - -C-style comments cannot be nested. For example, the following is not valid because the entire comment ends with the first */:

-

- - -/* This is the start of a comment.
- This is still part of the comment.
-/* This is an incorrect attempt at nesting a comment. */
- This is no longer in any comment. */

-

- - -C++-style comments start with the two characters // (slash, slash) and continue to the end of the physical line. They cannot be continued across multiple physical lines; to have one logical comment span multiple lines, each line must use the // pair.

-

- - -For example:

-

- - -// This is the start of a comment. The next line
-// is a new comment, even though it is logically
-// part of the previous comment.

-

- - -Shell-style (or perl-style, if you prefer) comments start with the character # (number sign) and continue to the end of the physical line, like C++ comments.

-

- - -For example:

-

- - -# This is the start of a comment. The next line
-# is a new comment, even though it is logically
-# part of the previous comment.

-

- - -WARNING: you cannot use the semicolon (';') character to start a comment such as you would in a zone file. The semicolon indicates the end of a configuration statement.

-
-
-
- +

    - - -5.2 - -Configuration File Grammar

    - + + +5.2 Running a Resolver Daemon +

- - -A BINDv9 configuration consists of statements and comments. Statements end with a semicolon. Statements and comments are the only elements that can appear without enclosing braces. Many statements contain a block of substatements, which are also terminated with a semicolon.

+ + +To use the lightweight resolver interface, the system must run the resolver daemon +lwresd +.

- - -The following statements are supported:

+ + +Applications using the lightweight resolver library will make UDP requests to the IPv4 loopback address (127.0.0.1) on port 921. The daemon will try to find the answer to the questions "what are the addresses for host +foo.example.com +?" and "what are the names for IPv4 address 204.152.184.79?"

- - - 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - - -acl -

-		 -

- - -defines a named IP address matching list, for access control and other uses.

-
-

- - - -controls -

-		 -

- - -declares control channels to be used by the -rndc - utility.

-
-

- - - -include -

-		 -

- - -includes a file.

-
-

- - - -key -

-		 -

- - -specifies key information for use in authentication and authorization using TSIG.

-
-

- - - -logging -

-		 -

- - -specifies what the server logs, and where the log messages are sent.

-
-

- - - -options -

-		 -

- - -controls global server configuration options and sets defaults for other statements.

-
-

- - - -server -

-		 -

- - -sets certain configuration options on a per-server basis.

-
-

- - - -trusted-keys -

-		 -

- - -defines trusted DNSSEC keys.

-
-

- - - -view -

-		 -

- - -defines a view.

-
-

- - - -zone -

-		 -

- - -defines a zone.

-
+ + +The daemon currently only looks in the DNS, but in the future it may use other sources such as +/etc/hosts +, NIS, etc.

- - -The -logging - and -options - statements may only occur once per configuration.

-
- -

- - -5.2.1 -acl - Statement Grammar

- -

-acl acl-name {
-    address_match_list
-};
-
-
-
- -

- + -5.2.2 -acl - - - Statement Definition and Usage

- -

- - The -acl - statement assigns a symbolic name to an address match list. It gets its name from a primary use of address match lists: Access Control Lists (ACLs).

-

- - -Note that an address match list's name must be defined with -acl - before it can be used elsewhere; no forward references are allowed.

-

- - -The following ACLs are built-in:

-

- - - 

- - - - - - - - - - - - - - - - - -
-

- - - -any -

-		 -

- - -Matches all hosts.

-
-

- - - -none -

-		 -

- - -Matches no hosts.

-
-

- - - -localhost -

-		 -

- - -Matches the IP addresses of all interfaces on the system.

-
-

- - - -localnets -

-		 -

- - -Matches any host on a network for which the system has an interface.

-
+lwresd + daemon is essentially a stripped-down, caching-only name server that answers requests using the lightweight resolver protocol rather than the DNS protocol. Because it needs to run on each host, it is designed to require no or minimal configuration. It uses the name servers listed on +nameserver + lines in +/etc/resolv.conf + as forwarders, but is also capable of doing the resolution autonomously if none are specified.

-
+
+

Return to BIND 9 Administrator Reference Manual table of contents.

-

- - -5.2.3 -controls - Statement Grammar

- - -
-controls {
-   [ inet (ip_addr|*) port ip_port allow { address_match_list };
-      [ inet...;[...]]]
-   [ unix string permission number owner number group number ;
-      [ unix...;[..]]]
-};
-
- - -
-
- -

- - -5.2.4 -controls - Statement Definition and Usage

- -

- - -The -controls - statement declares control channels to be used by system administrators to affect the operation of the local nameserver. These control channels are used by the -ndc - utility to send commands to and retrieve non-DNS results from a nameserver.

-

- - -A UNIX control channel is a "first in first out" (FIFO) named pipe in the file system, and access to it is controlled by normal file system permissions. It is created by -named - with the specified file mode bits (see the -chmod(1) - manual page), user and group owner. Note that, unlike -chmod -, the mode bits specified for -permission - will normally have a leading -0 - so the number is interpreted as octal. Also note that the user and group ownership specified as owner and group must be given as numbers, not names. It is recommended that the permissions be restricted to administrative personnel only to prevent random users on the system from having the ability to manage the local nameserver.

-

- - -An -inet - control channel is a TCP/IP socket accessible to the Internet, created at the specified -ip_port - on the specified -ip_addr -. It is recommended that 127.0.0.1 be the only -ip_addr - used, and this only if you trust all non-privileged users on the local host to manage your nameserver.

-

- - - -The - -controls - - statement is not yet implemented in BINDv9. The server always listens for control connections on IP address 127.0.0.1, port 953. -

-
-
- -

- - -5.2.5 -include - Statement Grammar

- -

- - - -include - -filename - -; -

-
-
- -

- - -5.2.6 -include - Statement Definition and Usage

- -

- - -The -include - statement inserts the specified file at the point that the -include - statement is encountered. The -include - statement facilitates the administration of configuration files by permitting the reading or writing of some things but not others. For example, the statement could include private keys that are readable only by a nameserver.

-
-
- -

- - -5.2.7 -key - Statement Grammar

- -

- - -

-
-key key_id {
-    algorithm string;
-    secret string;
-};
-
- -
-
- -

- - -5.2.8 -key - Statement Definition and Usage

- -

- - -The -key - statement defines a shared secret key for use with TSIG. See -See TSIG. -.

-

- - -The -key_id -, also known as the key name, is a domain name uniquely identifying the key. It can be used in a "server" statement to cause requests sent to that server to be signed with this key, or in address match lists to verify that incoming requests have been signed with a key matching this name, algorithm, and secret.

-

- - -The -algorithm_id - is a string that specifies a security/authentication algorithm. The only algorithm currently supported with TSIG authentication is -hmac-md5 -. The -secret_string - is the secret to be used by the algorithm, and is treated as a base-64 encoded string.

-
-
- -

- - -5.2.9 -logging - Statement Grammar

- -

-logging {
-   [ channel channel_name {
-     ( file path name
-         [ versions ( number | unlimited ) ]
-         [ size size spec ]
-       | syslog ( syslog_facility )
-       | null );
-     [ severity (critical | error | warning | notice |
-                 info | debug [ level ] | dynamic ); ]
-     [ print-category yes or no; ]
-     [ print-severity yes or no; ]
-     [ print-time yes or no; ]
-   }; ]
-   [ category category_name {
-     channel_name ; [ channel_name ; ... ]
-   }; ]
-   ...
-};
-
-
-
-

- -` -5.2.10 -logging - Statement Definition and Usage

- -

-The logging statement configures a wide variety of logging options for the nameserver. Its channel phrase associates output methods, format options and severity levels with a name that can then be used with the category phrase to select how various classes of messages are logged. -

-

-Only one logging statement is used to define as many channels and categories as are wanted. If there is no logging statement, the logging configuration will be: -

-
-logging {
-     category default { default_syslog; default_debug; };
-};
-
-

- - -In BINDv9, the logging configuration is only established when the entire configuration file has been parsed. In BIND 8, it was established as soon as the -logging - statement was parsed. When the server is starting up, all logging messages regarding syntax errors in the configuration file go to the default channels, or to standard error if the " --g -" option was specified.

-
- -
- - -5.2.10.1 The -channel - Phrase
- -

- - -All log output goes to one or more -channels -; you can make as many of them as you want.

-

- - -Every channel definition must include a clause that says whether messages selected for the channel go to a file, to a particular syslog facility, or are discarded. It can optionally also limit the message severity level that will be accepted by the channel (the default is -info -), and whether to include a -named --generated time stamp, the category name and/or severity level (the default is not to include any).

-

- - -The word -null - as the destination option for the channel will cause all messages sent to it to be discarded; in that case, other options for the channel are meaningless.

-

- - -The -file - clause can include limitations both on how large the file is allowed to become, and how many versions of the file will be saved each time the file is opened.

-

- - -The -size - option for files is simply a hard ceiling on log growth. If the file ever exceeds the size, then -named - will not write anything more to it until the file is reopened; exceeding the size does not automatically trigger a reopen. The default behavior is not to limit the size of the file.

-

- - -If you use the -version - log file option, then -named - will retain that many backup versions of the file by renaming them when opening. For example, if you choose to keep 3 old versions of the file -lamers.log - then just before it is opened -lamers.log.1 - is renamed to -lames.log.2 -, -lamers.log.0 - is renamed to -lamers.log.1 -, and -lamers.log - is renamed to -lamers.log.0 -. No rolled versions are kept by default; any existing log file is simply appended. The -unlimited - keyword is synonymous with -99 - in current BIND releases.

-

- - -Example usage of the size and versions options:

-

-    channel an_example_level {
-        file "lamers.log" versions 3 size 20m;
-        print-time yes;
-        print-category yes;
-    };
-
-

- - -The argument for the -syslog - clause is a syslog facility as described in the -syslog - man page. How -syslog - will handle messages sent to this facility is described in the -syslog.conf - man page. If you have a system which uses a very old version of -syslog - that only uses two arguments to the -openlog() - function, then this clause is silently ignored.

-

- - -The -severity - clause works like -syslog -'s "priorities," except that they can also be used if you are writing straight to a file rather than using -syslog -. Messages which are not at least of the severity level given will not be selected for the channel; messages of higher severity levels will be accepted.

-

- - -If you are using -syslog -, then the -syslog.conf - priorities will also determine what eventually passes through. For example, defining a channel facility and severity as -daemon - and -debug - but only logging -daemon.warning - via -syslog.conf - will cause messages of severity -info - and -notice - to be dropped. If the situation were reversed, with -named - writing messages of only -warning - or higher, then -syslogd - would print all messages it received from the channel.

-

- - -The server can supply extensive debugging information when it is in debugging mode. If the server's global debug level is greater than zero, then debugging mode will be active. The global debug level is set either by starting the -named - server with the " --d -" flag followed by a positive integer, or by running -rndc trace - ( -the latter method is not yet implemented -). The global debug level can be set to zero, and debugging mode turned off, by running -ndc notrace -. All debugging messages in the server have a debug level, and higher debug levels give more detailed output. Channels that specify a specific debug severity, for example:

-

-  channel specific_debug_level {
-      file "foo";
-      severity debug 3;
-  };
-
-

- - -will get debugging output of level 3 or less any time the server is in debugging mode, regardless of the global debugging level. Channels with -dynamic - severity use the server's global level to determine what messages to print.

-

- - -If -print-time - has been turned on, then the date and time will be logged. -print-time - may be specified for a -syslog - channel, but is usually pointless since -syslog - also prints the date and time. If -print-category - is requested, then the category of the message will be logged as well. Finally, if -print-severity - is on, then the severity level of the message will be logged. The -print- - options may be used in any combination, and will always be printed in the following order: time, category, severity. Here is an example where all three -print- - options are on:

-
-
- - - -28-Feb-2000 15:05:32.863 general: notice: running -
-

- - -There are four predefined channels that are used for -named -'s default logging as follows. How they are used is described in -The category Phrase -.

- -

-    channel default_syslog {
-        syslog daemon;				// end to syslog's daemon facility
-        severity info;				// only send priority info and higher
-    };
-    channel default_debug {
-        file "named.run";			// write to named.run in
-						// the working directory
-						// Note: stderr is used instead of
-						// "named.run"
-						// if the server is started
-						// with the '-f' option.
-        severity dynamic			// log at the server's
-						// current debug level
-    };
-    channel default_stderr {				// writes to stderr
-        file "<stderr>";			// this is illustrative only;
-						// there's currently no way of
-						// specifying an internal file
-						// descriptor in the configuration
-						// language.
-        severity info;				// only send priority info and higher
-    };
-    channel null {
-       null;					// toss anything sent to this channel
-    };
-
-

- - -The -default_debug - channel normally writes to a file -named.run - in the server's working directory. For security reasons, when the " --u -" command line option is used, the -named.run - file is created only after -named - has changed to the new UID, and any debug output generated while -named - is starting up and still running as root is discarded. If you need to capture this output, you must run the server with the " --g -" option and redirect standard error to a file.

-

- - -Once a channel is defined, it cannot be redefined. Thus you cannot alter the built-in channels directly, but you can modify the default logging by pointing categories at channels you have defined.

-
-
-
- -
- - -5.2.10.2 - -The -category - Phrase
- -

- - -There are many categories, so you can send the logs you want to see wherever you want, without seeing logs you don't want. If you don't specify a list of channels for a category, then log messages in that category will be sent to the -default - category instead. If you don't specify a default category, the following "default default" is used:

-

-    category default { default_syslog; default_debug; };
-
-As an example, let's say you want to log security events to a file, but you also want keep the default logging behavior. You'd specify the following: -

-channel my_security_channel {
-    file "my_security_file";
-    severity info;
-};
-category security {
-    my_security_channel;
-    default_syslog;
-    default_debug;
-};
-
-

- - -To discard all messages in a category, specify the -null channel:

-

-category xfer-out { null; };
-category notify { null; };
-
-

- - -Following are the available categories and brief descriptions of the types of log information they contain. -This list is still subject to change. -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - - -default -

-		 -

- - -The default category defines the logging options for those categories where no specific configuration has been defined. If you do not define a default category, the following definition is used:
- -category default { default_syslog; default_debug; }; -

-
-

- - - -general -

-		 -

- - -The catch-all. Many things still aren't classified into categories, and they all end up here.

-
-

- - - -database -

-		 -

- - -Messages relating to the databases used internally by the name server to store zone and cache data.

-
-

- - - -security -

-		 -

- - -Approval and denial of requests.

-
-

- - - -config -

-		 -

- - -Configuration file parsing and processing.

-
-

- - - -resolver -

-		 -

- - -DNS resolution, such as the recursive lookups performed on behalf of clients by a caching name server.

-
-

- - - -xfer-in -

-		 -

- - -Zone transfers the server is receiving.

-
-

- - - -xfer-out -

-		 -

- - -Zone transfers the server is sending.

-
-

- - - -notify -

-		 -

- - -The NOTIFY protocol.

-
-

- - - -client -

-		 -

- - -Processing of client requests.

-
-

- - - -network -

-		 -

- - -Network operations.

-
-

- - - -update -

-		 -

- - -Dynamic updates.

-
-
-
-
- -

- - -5.2.11 -options - Statement Grammar

- -

- - -This is the grammar of the -option - statement in the -named.conf - file:

-

-options {
-    [ version version_string; ]
-    [ directory path_name; ]
-    [ named-xfer path_name; ]
-    [ tkey-domain domainname; ]
-    [ tkey-dhkey keyname keyid; ]
-    [ dump-file path_name; ]
-    [ memstatistics-file path_name; ]
-    [ pid-file path_name; ]
-    [ statistics-file path_name; ]
-    [ auth-nxdomain yes_or_no; ]
-    [ deallocate-on-exit yes_or_no; ]
-    [ dialup yes_or_no; ]
-    [ fake-iquery yes_or_no; ]
-    [ fetch-glue yes_or_no; ]
-    [ has-old-clients yes_or_no; ]
-    [ host-statistics yes_or_no; ]
-    [ multiple-cnames yes_or_no; ]
-    [ notify yes_or_no; ]
-    [ recursion yes_or_no; ]
-    [ rfc2308-type1 yes_or_no; ]
-    [ use-id-pool yes_or_no; ]
-    [ maintain-ixfr-base yes_or_no; ]
-    [ forward ( only | first ); ]
-    [ forwarders { [ in_addr ; [ in_addr ; ... ] ] }; ]
-    [ check-names ( master | slave | response )( warn | fail | ignore ); ]
-    [ allow-query { address_match_list }; ]
-    [ allow-transfer { address_match_list }; ]
-    [ allow-recursion { address_match_list }; ]
-    [ blackhole { address_match_list }; ]
-    [ listen-on [ port ip_port ] { address_match_list }; ]
-    [ query-source [ address ( ip_addr | * ) ] [ port (ip_port | * ) ]; ]
-    [ max-transfer-time-in number; ]
-    [ max-transfer-time-out number; ]
-    [ max-transfer-idle-in number; ]
-    [ max-transfer-idle-out number; ]
-    [ tcp-clients number; ]
-    [ recursive-clients number; ]
-    [ serial-queries number; ]
-    [ transfer-format ( one-answer | many-answers ); ]
-    [ transfers-in  number; ]
-    [ transfers-out number; ]
-    [ transfers-per-ns number; ]
-    [ transfer-source ip_addr; ]
-    [ also-notify { ip_addr; [ ip_addr; ... ] }; ]   
-    [ max-ixfr-log-size number; ]
-    [ coresize size_spec ; ]
-    [ datasize size_spec ; ]
-    [ files size_spec ; ]
-    [ stacksize size_spec ; ]
-    [ cleaning-interval number; ]
-    [ heartbeat-interval number; ]
-    [ interface-interval number; ]
-    [ statistics-interval number; ]
-    [ topology { address_match_list }; ]
-    [ sortlist { address_match_list }; ]
-    [ rrset-order { order_spec ; [ order_spec ; ... ] ] };
-    [ lame-ttl number; ]
-    [ max-ncache-ttl number; ]
-    [ sig-validity-interval number ; ]
-    [ min-roots number; ]
-    [ use-ixfr yes_or_no ; ]
-    [ treat-cr-as-space yes_or_no ; ]};
-
-
-
- -

- - -5.2.12 -options - Statement Definition and Usage

- -

- - -The -options - statement sets up global options to be used by BIND. This statement may appear only once in a configuration file. If more than one occurrence is found, the first occurrence determines the actual options used, and a warning will be generated. If there is no -options - statement, an options block with each option set to its default will be used.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - - -version -

-		 -

- - -The version the server should report via a query of name -version.bind - in class -chaos -. The default is the real version number of this server.

-
-

- - - -directory -

-		 -

- - -The working directory of the server. Any non-absolute pathnames in the configuration file will be taken as relative to this directory. The default location for most server output files (e.g. -named.run -) is this directory. If a directory is not specified, the working directory defaults to ` -. -', the directory from which the server was started. The directory specified should be an absolute path.

-
-

- - - -named-xfer -

-		 -

- - - -This option is obsolete. - It was used in BIND 8 to specify the pathname to the -named-xfer - program. In BINDv9, no separate -named-xfer - program is needed; its functionality is built into the name server.

-
-

- - - -tkey-domain -

-		 -

- - -The domain appended to the names of all shared keys generated with -TKEY -. When a client requests a -TKEY - exchange, it may or may not specify the desired name for the key. If present, the name of the shared key will be " -client specified part -" + " -tkey-domain -". Otherwise, the name of the shared key will be " -random hex digits -" + " -tkey-domain -". In most cases, the -domainname - should be the server's domain name.

-
-

- - - -tkey-dhkey -

-		 -

- - -The Diffie-Hellman key used by the server to generate shared keys with clients using the Diffie-Hellman mode of -TKEY -. The server must be able to load the public and private keys from files in the working directory. In most cases, the keyname should be the server's host name.

-
-

- - - -dump-file -

-		 -

- - -The pathname of the file the server dumps the database to when it receives -SIGINT - signal ( -ndc dumpdb -). If not specified, the default is -named_dump.db -. -Not yet implemented in BINDv9. -

-
-

- - - -memstatistics-file -

-		 -

- - -The pathname of the file the server writes memory usage statistics to on exit. If not specified, the default is -named.memstats -. -Not yet implemented in BINDv9. -

-
-

- - - -pid-file -

-		 -

- - -The pathname of the file the server writes its process ID in. If not specified, the default is operating system dependent, but is usually
- -/var/run/named.pid - or -/etc/named.pid -. The pid-file is used by programs that want to send signals to the running nameserver.

-
-

- - - -statistics-file -

-		 -

- - -The pathname of the file the server appends statistics to. If not specified, the default is -named.stats -. -Not yet implemented in BINDv9 -.

-
-
- -
- - -5.2.12.1 - -Boolean Options
- -

- - - 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - - -auth-nxdomain -

-		 -

- - -If -yes -, then the -AA - bit is always set on NXDOMAIN responses, even if the server is not actually authoritative. The default is -no -; this is a change from BIND 8. If you are using very old DNS software, you may need to set it to -yes -.

-
-

- - - -deallocate-on-exit -

-		 -

- - -This option was used in BIND 8 to enable checking for memory leaks on exit. BINDv9 ignores the option and always performs the checks.

-
-

- - - -dialup -

-		 -

- - -If -yes -, then the server treats all zones as if they are doing zone transfers across a dial on demand dialup link, which can be brought up by traffic originating from this server. This has different effects according to zone type and concentrates the zone maintenance so that it all happens in a short interval, once every -heartbeat-interval - and hopefully during the one call. It also suppresses some of the normal zone maintenance traffic. The default is -no -.

-

- - -The -dialup - option may also be specified in the -zone - statement, in which case it overrides the -options dialup -statement.

-

- - -If the zone is a master then the server will send out a NOTIFY request to all the slaves. This will trigger the zone serial number check in the slave (providing it supports NOTIFY) allowing the slave to verify the zone while the connection is active.

-

- - -If the zone is a slave or stub then the server will suppress the regular "zone up to date" queries and only perform them when the
- -heartbeat-interval - expires. -Not yet implemented in BINDv9. -

-
-

- - - -fake-iquery -

-		 -

- - -In BIND 8, this option was used to enable simulating the obsolete DNS query type IQUERY. BINDv9 never does IQUERY simulation.

-
-

- - - -fetch-glue -

-		 -

- - -(Information present outside of the authoritative nodes in the zone is called -glue - information). If -yes - (the default), the server will fetch glue resource records it doesn't have when constructing the additional data section of a response. -fetch-glue - -no - - -can be used in conjunction with -recursion - -no - - -to prevent the server's cache from growing or becoming corrupted (at the cost of requiring more work from the client). -Not yet implemented in BINDv9. -

-
-

- - - -has-old-clients -

-		 -

- - -This option was incorrectly implemented in BIND 8, and is ignored by BINDv9. To achieve the intended effect of
- -has-old-clients - -yes -, specify the two separate options -auth-nxdomain - -yes - and -rfc2308-type1 - -no - instead.

-
-

- - - -host-statistics -

-		 -

- - -If -yes -, then statistics are kept for every host that the nameserver interacts with. The default is -no -. Note: turning on -host-statistics - can consume huge amounts of memory. -Not yet implemented in BINDv9. -

-
-

- - - -maintain-ixfr-base -

-		 -

- - - -This option is obsolete -. It was used in BIND 8 to determine whether a transaction log was kept for Incremental Zone Transfer. BINDv9 maintains a transaction log whenever possible. If you need to disable outgoing incremental zone transfers, use -provide-ixfr - -no -.

-
-

- - - -multiple-cnames -

-		 -

- - -This option was used in BIND 8 to allow a domain name to allow multiple CNAME records in violation of the DNS standards. BINDv9 currently does not check for multiple CNAMEs in zone data loaded from master files, but such checks may be introduced in a later release. BINDv9 always strictly enforces the CNAME rules in dynamic updates.

-
-

- - - -notify -

-		 -

- - -If -yes - (the default), DNS NOTIFY messages are sent when a zone the server is authoritative for changes. See Notify -, for more information. The -notify - option may also be specified in the -zone - statement, in which case it overrides the -options notify - statement. It would only be necessary to turn off this option if it caused slaves to crash -. -

-
-

- - - -recursion -

-		 -

- - -If -yes -, and a DNS query requests recursion, then the server will attempt to do all the work required to answer the query. If recursion is not on, the server will return a referral to the client if it doesn't know the answer. The default is -yes -. See also -fetch-glue - above.

-
-

- - - -rfc2308-type1 -

-		 -

- - -Setting this to -yes - will cause the server to send NS records along The default is -no -. -Not yet implemented in BINDv9 -.

-
-

- - - -use-id-pool -

-		 -

- - - -This option is obsolete -. BINDv9 always allocates query IDs from a pool.

-
-

- - - -treat-cr-as-space -

-		 -

- - -This option was used in BIND 8 to make the server treat " -\r -" characters the same way as -<space> -" " or " -\t -", to facilitate loading of zone files on a UNIX system that were generated on an NT or DOS machine. In BINDv9, both UNIX " -\n -" and NT/DOS " -\r\n -" newlines are always accepted, and the option is ignored.

-
-
-
- -
- - -5.2.12.2 Forwarding
- -

- - -The forwarding facility can be used to create a large site-wide cache on a few servers, reducing traffic over links to external nameservers. It can also be used to allow queries by servers that do not have direct access to the Internet, but wish to look up exterior names anyway. Forwarding occurs only on those queries for which the server is not authoritative and does not have the answer in its cache.

-

- - - 

- - - - - - - - - -
-

- - - -forward -

-		 -

- - -This option is only meaningful if the forwarders list is not empty. A value of -first -, the default, causes the server to query the forwarders first, and if that doesn't answer the question the server will then look for the answer itself. If -only - is specified, the server will only query the forwarders.

-
-

- - - -forwarders -

-		 -

- - -Specifies the IP addresses to be used for forwarding. The default is the empty list (no forwarding).

-
-

- - -Forwarding can also be configured on a per-domain basis, allowing for the global forwarding options to be overridden in a variety of ways. You can set particular domains to use different forwarders, or have different -forward only/first behavior -, or not forward at all. See -zone Statement Grammar - for more information.

-
-
- -
- - -5.2.12.3 - -Name Checking
- -

- - -The server can check domain names based upon their expected client contexts. For example, a domain name used as a hostname can be checked for compliance with the RFCs defining valid hostnames.

-

- - -Three checking methods are available:

-

- - - 

- - - - - - - - - - - - - -
-

- - - -ignore -

-		 -

- - -No checking is done.

-
-

- - - -warn -

-		 -

- - -Names are checked against their expected client contexts. Invalid names are logged, but processing continues normally.

-
-

- - - -fail -

-		 -

- - -Names are checked against their expected client contexts. Invalid names are logged, and the offending data is rejected.

-
-

- - -The server can check names in three areas: master zone files, slave zone files, and in responses to queries the server has initiated. If -check-names response fail - has been specified, and answering the client's question would require sending an invalid name to the client, the server will send a REFUSED response code to the client.

-

- - -The defaults are:

-

-    check-names master fail;
-    check-names slave warn;
-    check-names response ignore;
-

- - - -check-names - may also be specified in the -zone - statement, in which case it overrides the -options check-names - statement. When used in a -zone - statement, the area is not specified because it can be deduced from the zone type.

-
-

-Name checking is not yet implemented in BINDv9. -

-
-
-
- -
- - -5.2.12.4 - -Access Control
- -

- - -Access to the server can be restricted based on the IP address of the requesting system. See -Address Match Lists - for details on how to specify IP address lists.

-

- - - 

- - - - - - - - - - - - - - - - - -
-

- - - -allow-query -

-		 -

- - -Specifies which hosts are allowed to ask ordinary questions. -allow-query - may also be specified in the -zone - statement, in which case it overrides the -options allow-query - statement. If not specified, the default is to allow queries from all hosts.

-
-

- - - -allow-recursion -

-		 -

- - -Specifies which hosts are allowed to make recursive queries through this server. If not specified, the default is to allow recursive queries from all hosts.

-
-

- - - -allow-transfer -

-		 -

- - -Specifies which hosts are allowed to receive zone transfers from the server. -allow-transfer - may also be specified in the -zone - statement, in which case it overrides the -options allow-transfer - statement. If not specified, the default is to allow transfers from all hosts.

-
-

- - - -blackhole -

-		 -

- - -Specifies a list of addresses that the server will not accept queries from or use to resolve a query. Queries from these addresses will not be responded to. The default is -none -. -Not yet implemented in BINDv9. -

-
-
-
- -
- - -5.2.12.5 Interfaces
- -

- - -The interfaces and ports that the server will answer queries from may be specified using the -listen-on - option. -listen-on - takes an optional port, and an -address_match_list -. The server will listen on all interfaces allowed by the address match list. If a port is not specified, port 53 will be used.

-

- - -Multiple -listen-on - statements are allowed. For example,

-

- - - -listen-on { 5.6.7.8; };
-listen-on port 1234 { !1.2.3.4; 1.2/16; }; -

-

- - -will enable the nameserver on port 53 for the IP address 5.6.7.8, and on port 1234 of an address on the machine in net 1.2 that is not 1.2.3.4.

-

- - -If no -listen-on - is specified, the server will listen on port 53 on all interfaces.

-

- - -The -listen-on-v6 - option is used to specify the ports on which the server will listen for incoming queries sent using IPv6.

-

- - -The server does not bind a separate socket to each IPv6 interface address as it does for IPv4. Instead, it always listens on the IPv6 wildcard address. Therefore, the only values allowed for the -address_match_list - argument to the -listen-on-v6 - statement are " -{ any; } -" and " -{ none; } -".

-

- - -Multiple -listen-on-v6 - options can be used to listen on multiple ports:

-

- - - -listen-on-v6 port 53 { any; };
-listen-on-v6 port 1234 { any; }; -

-

- - -To make the server not listen on any IPv6 address, use

-

- - - -listen-on-v6 { none; }; -

-

- - -If no -listen-on-v6 -statement is specified, the server will listen on port 53 on the IPv6 wildcard address.

-
-
- -
- - -5.2.12.6 Query Address
- -

- - -If the server doesn't know the answer to a question, it will query other nameservers. -query-source - specifies the address and port used for such queries. For queries sent over IPv6, there is a separate -query-source-v6 - option. If -address - is -* - or is omitted, a wildcard IP address ( -INADDR_ANY -) will be used. If -port - is -* - or is omitted, a random unprivileged port will be used. The defaults are

-

- - - -query-source address * port *; -

-

- - - -query-source-v6 address * port * -

-

- - -Note: -query-source - currently applies only to UDP queries; TCP queries always use a wildcard IP address and a random unprivileged port.

-
-
- -
- - -5.2.12.7 - -Zone Transfers
- -

- - -BIND has mechanisms in place to facilitate zone transfers and set limits on the amount of load that transfers place on the system. The following options apply to zone transfers.

-

- - - 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - - -also-notify -

-		 -

- - -Defines a global list of IP addresses that are also sent NOTIFY messages whenever a fresh copy of the zone is loaded. This helps to ensure that copies of the zones will quickly converge on stealth servers. If an -also-notify - list is given in a -zone - statement, it will override the -options also-notify - statement. When a -zone notify - statement is set to -no -, the IP addresses in the global -also-notify - list will not be sent NOTIFY messages for that zone. The default is the empty list (no global notification list).

-
-

- - - -max-transfer-time-in -

-		 -

- - -Inbound zone transfers running longer than this many minutes will be terminated. The default is 120 minutes (2 hours).

-
-

- - - -max-transfer-idle-in -

-		 -

- - -Inbound zone transfers making no progress in this many minutes will be terminated. The default is 60 minutes (1 hour).

-
-

- - - -max-transfer-time-out -

-		 -

- - -Outbound zone transfers running longer than this many minutes will be terminated. The default is 120 minutes (2 hours).

-
-

- - - -max-transfer-idle-out -

-		 -

- - -Outbound zone transfers making no progress in this many minutes will be terminated. The default is 60 minutes

-

- - -(1 hour).

-
-

- - - -serial-queries -

-		 -

- - -Slave servers will periodically query master servers to find out if zone serial numbers have changed. Each such query uses a minute amount of the slave server's network bandwidth, but more importantly each query uses a small amount of memory in the slave server while waiting for the master server to respond. The -serial-queries -option sets the maximum number of concurrent serial-number queries allowed to be outstanding at any given time. The default is 4. Note: If a server loads a large (tens or hundreds of thousands) number of slave zones, then this limit should be raised to the high hundreds or low thousands, otherwise the slave server may never actually become aware of zone changes in the master servers. Beware, though, that setting this limit arbitrarily high can spend a considerable amount of your slave server's network, CPU, and memory resources. As with all tunable limits, this one should be changed gently and monitored for its effects. -Not yet implemented in BINDv9. -

-
-

- - - -transfer-format -

-		 -

- - -The server supports two zone transfer methods. -one-answer - uses one DNS message per resource record transferred. -many-answers - packs as many resource records as possible into a message. -many-answers - is more efficient, but is only known to be understood by BINDv9, BIND 8.x and patched versions of BIND 4.9.5. The default is -one-answer -. -transfer-format - may be overridden on a per-server basis by using the -server - statement.

-
-

- - - -transfers-in -

-		 -

- - -The maximum number of inbound zone transfers that can be running concurrently. The default value is -10 -. Increasing -transfers-in - may speed up the convergence of slave zones, but it also may increase the load on the local system.

-
-

- - - -transfers-out -

-		 -

- - -The maximum number of outbound zone transfers that can be running concurrently. Zone transfer requests in excess of the limit will be refused. The default value is -10 -.

-
-

- - - -transfers-per-ns -

-		 -

- - -The maximum number of inbound zone transfers that can be concurrently transferring from a given remote nameserver. The default value is -2 -. Increasing -transfers-per-ns - may speed up the convergence of slave zones, but it also may increase the load on the remote nameserver. -transfers-per-ns - may be overridden on a per-server basis by using the -transfers - phrase of the -server - statement.

-
-

- - - -transfer-source -

-		 -

- - - -transfer-source - determines which local address will be bound to IPv4 TCP connections used to fetch zones transferred inbound by the server. If not set, it defaults to a system controlled value which will usually be the address of the interface "closest to" the remote end. This address must appear in the remote end's -allow-transfer - option for the zone being transferred, if one is specified. This statement sets the -transfer-source - for all zones, but can be overridden on a per-zone basis by including a
- -transfer-source - statement within the -zone - block in the configuration file.

-
-

- - - -transfer-source-v6 -

-		 -

- - -Like -transfer-source -, but for zone transfers performed using IPv6.

-
-
-
- -
- - -5.2.12.8 Resource Limits
- -

- - -The server's usage of many system resources can be limited. Some operating systems don't support some of the limits. On such systems, a warning will be issued if the unsupported limit is used. Some operating systems don't support limiting resources.

-

- - -Scaled values are allowed when specifying resource limits. For example, -1G - can be used instead of -1073741824 - to specify a limit of one gigabyte. -unlimited - requests unlimited use, or the maximum available amount. -default - uses the limit that was in force when the server was started. See the description of -size_spec - in -Configuration File Grammar - for more details.

-

- - - 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - - -coresize -

-		 -

- - -The maximum size of a core dump. The default is -default -. -Not yet implemented in BINDv9. -

-
-

- - - -datasize -

-		 -

- - -The maximum amount of data memory the server may use. The default is -default -. -Not yet implemented in BINDv9. -

-
-

- - - -files -

-		 -

- - -The maximum number of files the server may have open concurrently. The default is -unlimited -. Note: on some operating systems the server cannot set an unlimited value and cannot determine the maximum number of open files the kernel can support. On such systems, choosing -unlimited - will cause the server to use the larger of the -rlim_max - for -RLIMIT_NOFILE - and the value returned by -sysconf(_SC_OPEN_MAX) -. If the actual kernel limit is larger than this value, use -limit files -to specify the limit explicitly. -Not yet implemented in BINDv9. -

-
-

- - - -max-ixfr-log-size -

-		 -

- - -The -max-ixfr-log-size - will be used in a future release of the server to limit the size of the transaction log kept for Incremental Zone Transfer. -Not yet implemented in BINDv9. -

-
-

- - - -recursive-clients -

-		 -

- - -The maximum number of simultaneous recursive lookup the server will perform on behalf of clients. The default is -100 -.

-
-

- - - -stacksize -

-		 -

- - -The maximum amount of stack memory the server may use. The default is -default -. -Not yet implemented in BINDv9. -

-
-

- - - -tcp-clients -

-		 -

- - -The maximum number of simultaneous client TCP connections that the server will accept. The default is -100 -.

-
-
-

-Resource limits are not yet implemented in BINDv9. -

-
-
-
- -
- - -5.2.12.9 Periodic Task Intervals
- -

- - - 

- - - - - - - - - - - - - - - - - -
-

- - - -cleaning-interval -

-		 -

- - -The server will remove expired resource records from the cache every -cleaning-interval -minutes. The default is -60 - minutes. If set to -0 -, no periodic cleaning will occur.

-
-

- - - -heartbeat-interval -

-		 -

- - -The server will perform zone maintenance tasks for all zones marked -dialup yes - whenever this interval expires. The default is -60 - minutes. Reasonable values are up to 1 day (1440 minutes). If set to -0 -, no zone maintenance for these zones will occur. -Not yet implemented in BINDv9. -

-
-

- - - -interface-interval -

-		 -

- - -The server will scan the network interface list every -interface-interval - minutes. The default is -60 - minutes. If set to -0 -, interface scanning will only occur when the configuration file is loaded. After the scan, listeners will be started on any new interfaces (provided they are allowed by the -listen-on - configuration). Listeners on interfaces that have gone away will be cleaned up.

-
-

- - - -statistics-interval -

-		 -

- - -Nameserver statistics will be logged every -statistics-interval - minutes. The default is -60 -. If set to -0 -, no statistics will be logged. -Not yet implemented in BINDv9. -

-
-
-
- -
- - -5.2.12.10 - -Topology
- -

- - -All other things being equal, when the server chooses a nameserver to query from a list of nameservers, it prefers the one that is topologically closest to itself. The -topology - statement takes an -address_match_list - and interprets it in a special way. Each top-level list element is assigned a distance. Non-negated elements get a distance based on their position in the list, where the closer the match is to the start of the list, the shorter the distance is between it and the server. A negated match will be assigned the maximum distance from the server. If there is no match, the address will get a distance which is further than any non-negated list element, and closer than any negated element. For example,

-

-    topology {
-    10/8;
-    !1.2.3/24;
-    { 1.2/16; 3/8; };
-    };
-
-

- - -will prefer servers on network 10 the most, followed by hosts on network 1.2.0.0 (netmask 255.255.0.0) and network 3, with the exception of hosts on network 1.2.3 (netmask 255.255.255.0), which is preferred least of all.

-

- - -The default topology is

-

- - - - topology { localhost; localnets; }; -

-

- - - -The - -topology - - option is not yet implemented in BINDv9. -

-
-
- -
- - -5.2.12.11 - -The -sortlist - Statement
- -

- - -Resource Records (RRs) are the data associated with the names in a domain name space. The data is maintained in the form of sets of RRs. The order of RRs in a set is, by default, not significant. Therefore, to control the sorting of records in a set resource records, or -RRset -, you must use the -sortlist - statement.

-

- - -RRs are explained more fully in -Types of Resource Records and When to Use Them -. Specifications for RRs are documented in RFC 1035.

-

- - -When returning multiple RRs the nameserver will normally return them in -Round Robin - - -order, that is, after each request the first RR is put at the end of the list. The client resolver code should rearrange the RRs as appropriate, that is, using any addresses on the local net in preference to other addresses. However, not all resolvers can do this or are correctly configured. When a client is using a local server the sorting can be performed in the server, based on the client's address. This only requires configuring the nameservers, not all the clients.

-

- - -The -sortlist - statement (see below) takes an -address_match_list -and interprets it even more specifically than the -topology - statement does (see -Topology -). Each top level statement in the -sortlist - must itself be an explicit -address_match_list - with one or two elements. The first element (which may be an IP address, an IP prefix, an ACL name or a nested -address_match_list -) of each top level list is checked against the source address of the query until a match is found.

-

- - -Once the source address of the query has been matched, if the top level statement contains only one element, the actual primitive element that matched the source address is used to select the address in the response to move to the beginning of the response. If the statement is a list of two elements, then the second element is treated like the -address_match_list - in a -topology - statement. Each top level element is assigned a distance and the address in the response with the minimum distance is moved to the beginning of the response.

-

- - -In the following example, any queries received from any of the addresses of the host itself will get responses preferring addresses on any of the locally connected networks. Next most preferred are addresses on the 192.168.1/24 network, and after that either the 192.168.2/24 or
-192.168.3/24 network with no preference shown between these two networks. Queries received from a host on the 192.168.1/24 network will prefer other addresses on that network to the 192.168.2/24 and
-192.168.3/24 networks. Queries received from a host on the 192.168.4/24 or the 192.168.5/24 network will only prefer other addresses on their directly connected networks.

-

-sortlist {
-    { localhost;					// IF   the local host
-        { localnets;					// THEN first fit on the
-            192.168.1/24;					//   following nets
-            { 192,168.2/24; 192.168.3/24; }; }; };
-    { 192.168.1/24;					// IF   on class C 192.168.1
-        { 192.168.1/24;					// THEN use .1, or .2 or .3
-            { 192.168.2/24; 192.168.3/24; }; }; };
-    { 192.168.2/24;					// IF   on class C 192.168.2
-        { 192.168.2/24;					// THEN use .2, or .1 or .3
-            { 192.168.1/24; 192.168.3/24; }; }; };
-    { 192.168.3/24;					// IF   on class C 192.168.3
-        { 192.168.3/24;					// THEN use .3, or .1 or .2
-            { 192.168.1/24; 192.168.2/24; }; }; };
-    { { 192.168.4/24; 192.168.5/24; };
-							// if .4 or .5, prefer that net
-    };
-};
-
-

- - -The following example will give reasonable behavior for the local host and hosts on directly connected networks. It is similar to the behavior of the address sort in BIND 8.x. Responses sent to queries from the local host will favor any of the directly connected networks. Responses sent to queries from any other hosts on a directly connected network will prefer addresses on that same network. Responses to other queries will not be sorted.

-

- - - -sortlist {
- { localhost; localnets; };
- { localnets; };
-}; -

-

- - - -The - -sortlist - - option is not yet implemented in BINDv9. -

-
-
- -
- - -5.2.12.12 - -RRset Ordering
- -

- - -When multiple records are returned in an answer it may be useful to configure the order of the records placed into the response. For example, the records for a zone might be configured always to be returned in the order they are defined in the zone file. Or perhaps a random shuffle of the records as they are returned is wanted. The - - statement permits configuration of the ordering made of the records in a multiple record response. The default, if no ordering is defined, is a cyclic ordering (round robin).

-

- - -An -order_spec - is defined as follows:

-
[ class class_name ][ type type_name ][ name "domain_name"]
-      order ordering
-
-

- - -If no class is specified, the default is -ANY -. If no type is specified, the default is -ANY -. If no name is specified, the default is " -* -".

-

- - -The legal values for -ordering - are:

-

- - - 

- - - - - - - - - - - - - -
-

- - - -fixed -

-		 -

- - -Records are returned in the order they are defined in the zone file.

-
-

- - - -random -

-		 -

- - -Records are returned in some random order.

-
-

- - - -cyclic -

-		 -

- - -Records are returned in a round-robin order.

-
-

- - -For example:

-

-    rrset-order {
-        class IN type A name "host.example.com" order random;
-        order cyclic;
-    };
-
-

- - -will cause any responses for type A records in class IN that have " -host.example.com -" as a suffix, to always be returned in random order. All other records are returned in cyclic order.

-

- - -If multiple -rrset-order - statements appear, they are not combined--the last one applies.

-

- - -If no -rrset-order - statement is specified, then a default one of:

-

-    rrset-order { class ANY type ANY name "*"; order cyclic ;
- };
-
-

- - -is used.

-

- - - -The - -rrset-order - - statement is not yet implemented in BINDv9. -

-
-
- -
- - -5.2.12.13 - -Tuning
- -

- - - 

- - - - - - - - - - - - - - - - - - - - - -
-

- - - -lame-ttl -

-		 -

- - -Sets the number of seconds to cache a lame server indication. 0 disables caching. (This is NOT recommended.) Default is -600 - (10 minutes). Maximum value is -1800 - (30 minutes). -Not yet implemented in BINDv9. -

-
-

- - - -max-ncache-ttl -

-		 -

- - -To reduce network traffic and increase performance the server stores negative answers. -max-ncache-ttl - is used to set a maximum retention time for these answers in the server in seconds. The default
- -max-ncache-ttl - is -10800 - seconds (3 hours).
- -max-ncache-ttl - cannot exceed 7 days and will be silently truncated to 7 days if set to a greater value.

-
-

- - - -max-cache-ttl -

-		 -

- - - -max-cache-ttl - sets the maximum time for which the server will cache ordinary (positive) answers. The default is one week (7 days).

-
-

- - - -min-roots -

-		 -

- - -The minimum number of root servers that is required for a request for the root servers to be accepted. Default is -2 -. -Not yet implemented in BINDv9. -

-
-

- - - -sig-validity-interval -

-		 -

- - -Specifies the number of days into the future when DNSSEC signatures automatically generated as a result of dynamic updates (see -See Dynamic Update. - ) will expire. The default is -30 - days. The signature inception time is unconditionally set to one hour before the current time to allow for a limited amount of clock skew.

-
-
-
- -
- - -5.2.12.14 Deprecated Features
- -

- - - -use-ixfr - is deprecated in BINDv9. If you need to disable IXFR to a particular server or servers see the information on the -provide-ixfr - option in -server Statement Grammar -. See also the description of Incremental Transfer (IXFR) in the section -Incremental Zone Transfers (IXFR) -.

-
-
-
- -

- - -5.2.13 -server - - - Statement Grammar

- -

-server ip_addr {
-     [ bogus yes_or_no ; ]
-
-    [ provide-ixfr yes_or_no ; ]
-
-    [ request-ixfr yes_or_no ; ]
-
-    [ transfers number ; ]
-
-    [ transfer-format ( one-answer | many-answers ) ; ]
-
-    [ keys { string ; [ string ; [...]] } ; ]

-};
-
-
-
- -

- - -5.2.14 -server - Statement Definition and Usage

- -

- - -The -server - statement defines the characteristics to be associated with a remote nameserver.

-

- - -If you discover that a remote server is giving out bad data, marking it as bogus will prevent further queries to it. The default value of -bogus - is -no -. -The - -bogus - - clause is not yet implemented in BINDv9. -

-

- - -The -provide-ixfr - clause determines whether the local server, acting as master, will respond with an incremental zone transfer when the given remote server, a slave, requests it. If set to -yes -, incremental transfer will be provided whenever possible. If set to -no -, all transfers to the remote server will be nonincremental. If not set, the value of the -provide-ixfr -option in the global options block is used as a default.

-

- - -The -request-ixfr - clause determines whether the local server, acting as a slave, will request incremental zone transfers from the given remote server, a master. If not set, the value of the -request-ixfr - option in the global options block is used as a default.

-

- - -IXFR requests to servers that do not support IXFR will automatically fall back to AXFR. Therefore, there is no need to manually list which servers support IXFR and which ones do not; the global default of -yes - should always work. The purpose of the -provide-ixfr - and -request-ixfr - clauses is to make it possible to disable the use of IXFR even when both master and slave claim to support it, for example if one of the servers is buggy and crashes or corrupts data when IXFR is used.

-

- - -The server supports two zone transfer methods. The first, -one-answer -, uses one DNS message per resource record transferred. -many-answers - packs as many resource records as possible into a message. -many-answers - is more efficient, but is only known to be understood by BINDv9, BIND 8.x, and patched versions of BIND 4.9.5. You can specify which method to use for a server with the -transfer-format -option. If -transfer-format -is not specified, the -transfer-format - specified by the -options - statement will be used.

-

- - - -transfers - is used to limit the number of concurrent inbound zone transfers from the specified server. If no -transfers - clause is specified, the limit is set according to the -transfers-per-ns - option.

-

- - -The -keys - clause is used to identify a -key_id -defined by the -key - statement, to be used for transaction security when talking to the remote server. The -key - statement must come before the -server - statement that references it. When a request is sent to the remote server, a request signature will be generated using the key specified here and appended to the message. A request originating from the remote server is not required to be signed by this key.

-

- - -Although the grammar of the -keys - clause allows for multiple keys, only a single key per server is currently supported.

-
-
- -

- - -5.2.15 -trusted-keys - Statement Grammar

- -
-trusted-keys {

-    string number number number string ;

-    [ string number number number string ; [...]]

-};
-
-
-
- -

- - -5.2.16 -trusted-keys - Statement Definition and Usage

- -

- - -The -trusted-keys - statement defines DNSSEC security roots. DNSSEC is described in -DNSSEC -. A security root is defined when the public key for a non-authoritative zone is known, but cannot be securely obtained through DNS, either because it is the DNS root zone or its parent zone is unsigned. Once a key has been configured as a trusted key, it is treated as if it had been validated and proven secure. The resolver attempts DNSSEC validation on all DNS data in subdomains of a security root.

-

- - -The -trusted-keys - statement can contain multiple key entries, each consisting of the key's domain name, flags, protocol, algorithm, and the base-64 representation of the key data.

-
-
- -

- - -5.2.17 -view - Statement Grammar

- -
-view view name {

-      match_clients { address_match_list } ;

-      [view_option; ...]

-      [zone_statement; ...]]

-};
-
-
-
- -

- - -5.2.18 -view - Statement Definition and Usage

- -

- - -The -view - statement is a powerful new feature of BINDv9 that lets a name server answer a DNS query differently depending on who is asking. It is particularly useful for implementing split DNS setups without having to run multiple servers.

-

- - -Each -view - statement defines a view of the DNS namespace that will be seen by those clients whose IP addresses match the -address_match_list - of the view's -match-clients - clause. The order of the -view - statements is significant--a client query will be resolved in the context of the first -view - whose -match-clients -list matches the client's IP address.

-

- - -Zones defined within a -view - statement will be only be accessible to clients that match the -view -. By defining a zone of the same name in multiple views, different zone data can be given to different clients, for example, "internal" and "external" clients in a split DNS setup.

-

- - -Many of the options given in the -options - statement can also be used within a -view - statement, and then apply only when resolving queries with that view. When no a view-specific value is given, the value in the -options - statement is used as a default. Also, zone options can have default values specified in the -view - statement; these view-specific defaults take precedence over those in the -options - statement.

-

- - -Views are class specific. If no class is given, class IN is assumed.

-

- - -If there are no -view - statements in the config file, a default view that matches any client is automatically created in class IN, and any -zone - statements specified on the top level of the configuration file are considered to be part of this default view. If any explicit -view - statements are present, all -zone - statements must occur inside -view - statements.

-

- - -Here is an example of a typical split DNS setup implemented using -view - statements.

-

-view "internal" {
-               // This should match our internal networks.
-      match-clients { 10.0.0.0/8; };
-               // Provide recursive service to internal clients only.
-      recursion yes;
-               // Provide a complete view of the example.com zone
-               // including addresses of internal hosts.
-      zone "example.com" {
-            type master;
-            file "example-internal.db";
-      };
-  };
-
-

-  view "external" {
-      match-clients { any; };
-               // Refuse recursive service to external clients.
-      recursion no;
-               // Provide a restricted view of the example.com zone
-               // containing only publicly accessible hosts.
-      zone "example.com" {
-           type master;
-           file "example-external.db";
-      };
-  };
-
-
-
- -

- - -5.2.19 -zone - - - Statement Grammar

- -

-zone zone name [class] [{
-   type ( master|slave|hint|stub|forward) ;
-       [ allow-query { address_match_list } ; ]
-       [ allow-transfer { address_match_list } ; ]
-       [ allow-update { address_match_list } ; ]
-       [ update-policy { update_policy_rule [...] } ; ]
-       [ allow-update-forwarding{ address_match_list } ; ]
-       [ also-notify { [ ip_addr ;[ip_addr ; [...]]] } ; ]
-       [ check-names (warn|fail|ignore) ; ]
-       [ dialup true_or_false ; ]
-       [ file string ; ]
-       [ forward (only|first) ; ]
-       [ forwarders { [ ip_addr ; [ ip_addr ; [...]]] } ; ]
-       [ ixfr-base string ; ]
-       [ ixfr-tmp-file string ;]
-       [ maintain-ixfr-base true_or_false ; ]
-       [ masters [port number]{ ip_addr ; [ip_addr ; [...]] } ;  ]
-       [ max-ixfr-log-size number ; ]
-       [ max-transfer-idle-in number ; ]
-       [ max-transfer-idle-out number ; ]
-       [ max-transfer-time-in number ; ]
-       [ max-transfer-time-out number ; ]
-       [ notify true_or_false ; ]
-       [ pubkey number number number string ; ]
-       [ transfer-source (ip_addr | *) ; ]
-       [ sig-validity-interval number ; ]}]
-;
-
-
- -

- - -5.2.20 -zone - Statement Definition and Usage

- -
- -
- - -5.2.20.1 Zone Types
- - - - - - - - - - - - - - - - - - - - - -
-

- - - -master -

-		 -

- - -The server has a master copy of the data for the zone and will be able to provide authoritative answers for it.

-
-

- - - -slave -

-		 -

- - -A slave zone is a replica of a master zone. The masters list specifies one or more IP addresses that the slave contacts to update its copy of the zone. If a port is specified, the slave then checks to see if the zone is current and zone transfers will be done to the port given. If a file is specified, then the replica will be written to this file whenever the zone is changed, and reloaded from this file on a server restart. Use of a file is recommended, since it often speeds server start-up and eliminates a needless waste of bandwidth. Note that for large numbers (in the tens or hundreds of thousands) of zones per server, it is best to use a two level naming scheme for zone file names. For example, a slave server for the zone -example.com - might place the zone contents into a file called
- -ex/example.com - where -ex/ -is just the first two letters of the zone name. (Most operating systems behave very slowly if you put 100K files into a single directory.)

-
-

- - - -stub -

-		 -

- - -A stub zone is like a slave zone, except that it replicates only the NS records of a master zone instead of the entire zone. -Stub zones are not yet implemented in BINDv9. -

-
-

- - - -forward -

-		 -

- - -A "forward zone" is a way to configure forwarding on a per-domain basis. A -zone - statement of type -forward - can contain a -forward - and/or -forwarders - statement, which will apply to queries within the domain given by the zone name. If no -forwarders - statement is present or an empty list for -forwarders - is given, then no forwarding will be done for the domain, cancelling the effects of any forwarders in the -options - statement. Thus if you want to use this type of zone to change the behavior of the global -forward - option (that is, "forward first to", then "forward only", or vice versa, but want to use the same servers as set globally) you need to respecify the global forwarders. -Domain-specific forwarding is not yet implemented in BINDv9. -

-
-

- - - -hint -

-		 -

- - -The initial set of root nameservers is specified using a "hint zone". When the server starts up, it uses the root hints to find a root nameserver and get the most recent list of root nameservers. If no hint zone is specified for class IN, the server users a compiled-in default set of root servers hints. Classes other than IN have no built-in defaults hints.

-
- -
-
- -
- - -5.2.20.2 Class
- -

- - -The zone's name may optionally be followed by a class. If a class is not specified, class -IN - (for -Internet -), is assumed. This is correct for the vast majority of cases.

-

- - -The -hesiod - - -class is named for an information service from MIT's Project Athena. It is used to share information about various systems databases, such as users, groups, printers and so on. The keyword -HS - is a synonym for hesiod.

-

- - -Another MIT development is CHAOSnet, a LAN protocol created in the mid-1970s. Zone data for it can be specified with the -CHAOS - class.

-
-
- -
- - -5.2.20.3 Zone Options
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - - -allow-query -

-		 -

- - -See the description of -allow-query - under -Access Control -.

-
-

- - - -allow-transfer -

-		 -

- - -See the description of -allow-transfer - under -Access Control -.

-
-

- - - -allow-update -

-		 -

- - -Specifies which hosts are allowed to submit Dynamic DNS updates for master zones. The default is to deny updates from all hosts.

-
-

- - - -update-policy -

-		 -

- - -Specifies a "Simple Secure Update" policy. See description in -Dynamic Update Policies -.

-
-

- - - -allow-update-forwarding -

-		 -

- - -Specifies which hosts are allowed to submit Dynamic DNS updates to slave zones to be forwarded to the master. The default is to deny update forwarding from all hosts. -Update forwarding is not yet implemented. -

-
-

- - - -also-notify -

-		 -

- - -Only meaningful if -notify - is active for this zone. The set of machines that will receive a -DNS NOTIFY - message for this zone is made up of all the listed nameservers (other than the primary master) for the zone plus any IP addresses specified with -also-notify -.
- -also-notify - is not meaningful for stub zones. The default is the empty list -. -

-
-

- - - -check-names -

-		 -

- - -See -Name Checking -.
- -Not yet implemented in BINDv9. -

-
-

- - - -dialup -

-		 -

- - -See the description of -dialup - under -Boolean Options -.
- -Not yet implemented in BINDv9. -

-
-

- - - -forward -

-		 -

- - -Only meaningful if the zone has a forwarders list. The -only - value causes the lookup to fail after trying the forwarders and getting no answer, while -first - would allow a normal lookup to be tried.
- -Not yet implemented in BINDv9. -

-
-

- - - -forwarders -

-		 -

- - -Used to override the list of global forwarders. If it is not specified in a zone of type -forward -, no forwarding is done for the zone; the global options are not used.

-

- - - -Not yet implemented in BINDv9. -

-
-

- - - -ixfr-base -

-		 -

- - -Was used in BIND 8 to specify the name of the transaction log (journal) file for dynamic update and IXFR. BINDv9 ignores the option and constructs the name of the journal file by appending ". -jnl -" to the name of the zone file.

-
-

- - - -max-transfer-time-in -

-		 -

- - -See the description of
- -max-transfer-time-in - under -Zone Transfers -.

-
-

- - - -max-transfer-idle-in -

-		 -

- - -See the description of
- -max-transfer-idle-in - under -Zone Transfers -.

-
-

- - - -max-transfer-time-out -

-		 -

- - -See the description of
- -max-transfer-time-out - under -Zone Transfers -.

-
-

- - - -max-transfer-idle-out -

-		 -

- - -See the description of
- -max-transfer-idle-out - under -Zone Transfers -.

-
-

- - - -notify -

-		 -

- - -See the description of -notify - under -Boolean Options -.

-
-

- - - -pubkey -

-		 -

- - -In BIND 8, this option was intended for specifying a public zone key for verification of signatures in DNSSEC signed zones when they are loaded from disk. BINDv9 does not verify signatures on loading and ignores the option.

-
-

- - - -sig-validity-interval -

-		 -

- - -See the description of -sig-validity-interval - under -Tuning -.

-
-

- - - -transfer-source -

-		 -

- - -Determines which local address will be bound to the TCP connection used to fetch this zone. If not set, it defaults to a system controlled value which will usually be the address of the interface -closest to - the remote end. This address must appear in the remote end's -allow-transfer - option for this zone if one is specified.

-
- -
-
- -
- - -5.2.20.4 - -Dynamic Update Policies
- -

- - -BINDv9 supports two alternative methods of granting clients the right to perform dynamic updates to a zone, configured by the -allow-update - and -update-policy - option, respectively.

-

- - -The -allow-update - clause works the same way as in previous versions of BIND. It grants given clients the permission to update any record of any name in the zone.

-

- - -The -update-policy - clause is new in BINDv9 and allows more fine-grained control over what updates are allowed. A set of rules is specified, where each rule either grants or denies permissions for one or more names to be updated by one or more identities. If the dynamic update request message is signed (that is, it includes either a TSIG or SIG(0) record), the identity of the signer can be determined.

-

- - -Rules are specified in the -update-policy - zone option, and are only meaningful for master zones. When the -update-policy - statement is present, it is a configuration error for the -allow-update - statement to be present. The -update-policy - statement only examines the signer of a message; the source address is not relevant.

-

- - -A rule definition looks like:

-

-( grant | deny ) identity nametype name [ types ]
-
-

- - -Each rule grants or denies privileges. Once a messages has successfully matched a rule, the operation is immediately granted or denied and no further rules are examined. A rule is matched when the signer matches the identity field, the name matches the name field, and the type is specified in the type field.

-

- - -The identity field specifies a name or a wildcard name. The nametype field has 4 values: -name -, -subdomain -, -wildcard -, and -self - - -.

- - - - - - - - - - - - - - - - - -
-
- - - -name -
-		 -

- - -Matches when the updated name is the same as the name in the name field.

-
-
- - - -subdomain -
-		 -

- - -Matches when the updated name is a subdomain of the name in the name field.

-
-
- - - -wildcard -
-		 -

- - -Matches when the updated name is a valid expansion of the wildcard name in the name field.

-
-
- - - -self -
-		 -

- - -Matches when the updated name is the same as the message signer. The name field is ignored.

-
-

- - -If no types are specified, the rule matches all types except SIG, NS, SOA, and NXT. Types may be specified by name, including "ANY" (ANY matches all types except NXT, which can never be updated).

-
-
-
-
- -

- - -5.3 Zone File

- -
- -

- - -5.3.1 - -Types of Resource Records and When to Use Them

- -

- - -This section, largely borrowed from RFC 1034, describes the concept of a Resource Record (RR) and explains when each is used. Since the publication of RFC 1034, several new RRs have been identified and implemented in the DNS. These are also included.

-
- -
- - -5.3.1.1 Resource Records
- -

- - -A domain name identifies a node. Each node has a set of resource information, which may be empty. The set of resource information associated with a particular name is composed of separate RRs. The order of RRs in a set is not significant and need not be preserved by nameservers, resolvers, or other parts of the DNS. However, sorting of multiple RRs is permitted for optimization purposes, for example, to specify that a particular nearby server be tried first. See -The sortlist Statement - and -RRset Ordering - for details.

-

- - -The components of a Resource Record are

- - - - - - - - - - - - - - - - - - - - - -
-

- - -owner name

-		 -

- - -the domain name where the RR is found.

-
-

- - -type

-		 -

- - -an encoded 16 bit value that specifies the type of the resource in this resource record. Types refer to abstract resources.

-
-

- - -TTL

-		 -

- - -the time to live of the RR. This field is a 32 bit integer in units of seconds, and is primarily used by resolvers when they cache RRs. The TTL describes how long a RR can be cached before it should be discarded.

-
-

- - -class

-		 -

- - -an encoded 16 bit value that identifies a protocol family or instance of a protocol.

-
-

- - -RDATA

-		 -

- - -the type and sometimes class-dependent data that describes the resource.

-
-

- - -The following are -types - of valid RRs (some of these listed, although not obsolete, are experimental (x) or historical (h) and no longer in general use):

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - -A

-		 -

- - -a host address.

-
-

- - -A6

-		 -

- - -an IPv6 address.

-
-

- - -AAAA

-		 -

- - -Obsolete format of IPv6 address

-
-

- - -AFSDB

-		 -

- - -(x) location of AFS database servers. Experimental.

-
-

- - -CNAME

-		 -

- - -identifies the canonical name of an alias.

-
-

- - -DNAME

-		 -

- - -for delegation of reverse addresses. Replaces the domain name specified with another name to be looked up. Described in RFC 2672.

-
-

- - -HINFO

-		 -

- - -identifies the CPU and OS used by a host.

-
-

- - -ISDN

-		 -

- - -(x) representation of ISDN addresses. Experimental.

-
-

- - -KEY

-		 -

- - -stores a public key associated with a DNS name.

-
-

- - -LOC

-		 -

- - -(x) for storing GPS info. See RFC 1876. Experimental.

-
-

- - -MX

-		 -

- - -identifies a mail exchange for the domain. See RFC 974 for details.

-
-

- - -NS

-		 -

- - -the authoritative nameserver for the domain.

-
-

- - -NXT

-		 -

- - -used in DNSSEC to securely indicate that RRs with an owner name in a certain name interval do not exist in a zone and indicate what RR types are present for an existing name. See RFC 2535 for details.

-
-

- - -PTR

-		 -

- - -a pointer to another part of the domain name space.

-
-

- - -RP

-		 -

- - -(x) information on persons responsible for the domain. Experimental.

-
-

- - -RT

-		 -

- - -(x) route-through binding for hosts that do not have their own direct wide area network addresses. Experimental.

-
-

- - -SIG

-		 -

- - -("signature") contains data authenticated in the secure DNS. See RFC 2535 for details.

-
-

- - -SOA

-		 -

- - -identifies the start of a zone of authority.

-
-

- - -SRV

-		 -

- - -information about well known network services (replaces WKS).

-
-

- - -WKS

-		 -

- - -(h) information about which well known network services, such as SMTP, that a domain supports. Historical, replaced by newer RR SRV.

-
-

- - -X25

-		 -

- - -(x) representation of X.25 network addresses. Experimental.

-
-

- - -The following -classes - of resource records are currently valid in the DNS:

- - - - - - - - -
-

- - -IN

-		 -

- - -the Internet system.

-
-

- - -For information about other, older classes of RRs, see -Classes of Resource Records - of the Appendix.

-
-

- - - -RDATA - is the type-dependent or class-dependent data that describes the resource:

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-

- - -A

-		 -

- - -for the IN class, a 32 bit IP address.

-
-

- - -A6

-		 -

- - -maps a domain name to an IPv6 address, with a provision for indirection for leading "prefix" bits.

-
-

- - -CNAME

-		 -

- - -a domain name.

-
-

- - -DNAME

-		 -

- - -provides alternate naming to an entire subtree of the domain name space, rather than to a single node. It causes some suffix of a queried name to be substituted with a name from the DNAME record's RDATA.

-
-

- - -MX

-		 -

- - -a 16 bit preference value (lower is better) followed by a host name willing to act as a mail exchange for the owner domain.

-
-

- - -NS

-		 -

- - -a fully qualified domain name.

-
-

- - -PTR

-		 -

- - -a fully qualified domain name.

-
-

- - -SOA

-		 -

- - -several fields.

-
-

- - -The owner name is often implicit, rather than forming an integral part of the RR. For example, many nameservers internally form tree or hash structures for the name space, and chain RRs off nodes. The remaining RR parts are the fixed header (type, class, TTL) which is consistent for all RRs, and a variable part (RDATA) that fits the needs of the resource being described.

-

- - -The meaning of the TTL field is a time limit on how long an RR can be kept in a cache. This limit does not apply to authoritative data in zones; it is also timed out, but by the refreshing policies for the zone. The TTL is assigned by the administrator for the zone where the data originates. While short TTLs can be used to minimize caching, and a zero TTL prohibits caching, the realities of Internet performance suggest that these times should be on the order of days for the typical host. If a change can be anticipated, the TTL can be reduced prior to the change to minimize inconsistency during the change, and then increased back to its former value following the change.

-

- - -The data in the RDATA section of RRs is carried as a combination of binary strings and domain names. The domain names are frequently used as "pointers" to other data in the DNS.

-
-
- -
- - -5.3.1.2 Textual expression of RRs
- -

- - -RRs are represented in binary form in the packets of the DNS protocol, and are usually represented in highly encoded form when stored in a nameserver or resolver. In the examples provided in RFC 1034, a style similar to that used in master files was employed in order to show the contents of RRs. In this format, most RRs are shown on a single line, although continuation lines are possible using parentheses.

-

- - -The start of the line gives the owner of the RR. If a line begins with a blank, then the owner is assumed to be the same as that of the previous RR. Blank lines are often included for readability.

-

- - -Following the owner, we list the TTL, type, and class of the RR. Class and type use the mnemonics defined above, and TTL is an integer before the type field. In order to avoid ambiguity in parsing, type and class mnemonics are disjoint, TTLs are integers, and the type mnemonic is always last. The IN class and TTL values are often omitted from examples in the interests of clarity.

-

- - -The resource data or RDATA section of the RR are given using knowledge of the typical representation for the data.

-

- - -For example, we might show the RRs carried in a message as:

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - -ISI.EDU. - - - - - - -MX - - - - - - -10 VENERA.ISI.EDU. - -
- - - - - -  - - - - - -MX - - - - - - -10 VAXA.ISI.EDU - -
- - - - -VENERA.ISI.EDU - - - - - - -A - - - - - - -128.9.0.32 - -
- - - - - -  - - - - - -A - - - - - - -10.1.0.52 - -
- - - - -VAXA.ISI.EDU - - - - - - -A - - - - - - -10.2.0.27 - -
- - - - - -  - - - - - -A - - - - - - -128.9.0.33 - -
-

- - -The MX RRs have an RDATA section which consists of a 16 bit number followed by a domain name. The address RRs use a standard IP address format to contain a 32 bit internet address.

-

- - -This example shows six RRs, with two RRs at each of three domain names.

-

- - -Similarly we might see:

- - - - - - - - - - - -
- - - - -XX.LCS.MIT.EDU. IN - - - - - - -A - - - - - - -10.0.0.44 - -
- - - - -CH - - - - - - -A - - - - - - -MIT.EDU. 2420 - -
-

- - -This example shows two addresses for -XX.LCS.MIT.EDU -, each of a different class.

-
-
-
- -

- - -5.3.2 Discussion of MX Records

- -

- - -As described above, domain servers store information as a series of resource records, each of which contains a particular piece of information about a given domain name (which is usually, but not always, a host). The simplest way to think of a RR is as a typed pair of datum, a domain name matched with relevant data, and stored with some additional type information to help systems determine when the RR is relevant.

-

- - -MX records are used to control delivery of email. The data specified in the record is a priority and a domain name. The priority controls the order in which email delivery is attempted, with the lowest number first. If two priorities are the same, a server is chosen randomly. If no servers at a given priority are responding, the mail transport agent will fall back to the next largest priority. Priority numbers do not have any absolute meaning - they are relevant only respective to other MX records for that domain name. The domain name given is the machine to which the mail will be delivered. It -must - have an associated A record--a CNAME is not sufficient.

-

- - -For a given domain, if there is both a CNAME record and an MX record, the MX record is in error, and will be ignored. Instead, the mail will be delivered to the server specified in the MX record pointed to by the CNAME.

-

- - -For example:

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - -example.com. - - - - - - -IN - - - - - - -MX - - - - - - -10 - - - - - - -mail.example.com. - -
- - - - - -  - - - - - -IN - - - - - - -MX - - - - - - -10 - - - - - - -mail2.example.com. - -
- - - - - -  - - - - - -IN - - - - - - -MX - - - - - - -20 - - - - - - -mail.backup.org. - -
- - - - -mail.example.com. - - - - - - -IN - - - - - - -A - - - - - - -10.0.0.1 - - - - - - - -  -
- - - - -mail2.example.com. - - - - - - -IN - - - - - - -A - - - - - - -10.0.0.2 - - - - - - - -  -
-

- - -Mail delivery will be attempted to -mail.example.com - and -mail2.example.com - (in any order), and if neither of those succeed, delivery to -mail.backup.org - will be attempted.

-
-
- -

- - -5.3.3 - -Setting TTLs

- -

- - -The time to live of the RR field is a 32 bit integer represented in units of seconds, and is primarily used by resolvers when they cache RRs. The TTL describes how long a RR can be cached before it should be discarded. The following three types of TTL are currently used in a zone file.

-

- - - 

- - - - - - - - - - - - - -
-

- - -SOA

-		 -

- - -The last field in the SOA is the negative caching TTL. This controls how long other servers will cache no-such-domain (NXDOMAIN) responses from you.

-

- - -The maximum time for negative caching is 3 hours (3h).

-
-

- - -$TTL

-		 -

- - -The $TTL directive at the top of the zone file (before the SOA) gives a default TTL for every RR without a specific TTL set.

-
-

- - -RR TTLs

-		 -

- - -Each RR can have a TTL as the second field in the RR, which will control how long other servers can cache the it.

-
-

- - -All of these TTLs default to units of seconds, though units can be explicitly specified, for example, -1h30m -.

-
-
- -

- - -5.3.4 Inverse Mapping in IPv4

- -

- - -Reverse name resolution (that is, translation from IP address to name) is achieved by means of the -in-addr.arpa - domain and PTR records. Entries in the in-addr.arpa domain are made in least-to-most significant order, read left to right. This is the opposite order to the way IP addresses are usually written. Thus, a machine with an IP address of 10.1.2.3 would have a corresponding in-addr.arpa name of
-3.2.1.10.in-addr.arpa. This name should have a PTR resource record whose data field is the name of the machine or, optionally, multiple PTR records if the machine has more than one name. For example, in the -example.com - domain:

-

-
- 
- - - - - - - - - -
-

- - - -$ORIGIN -

-		 -

- - - -2.1.10.in-addr.arpa -

-
-

- - - -3 -

-		 -

- - - -IN PTR foo.example.com. -

-
-

- - -(Note: The -$ORIGIN - lines in the examples are for providing context to the examples only--they do not necessarily appear in the actual usage. They are only used here to indicate that the example is relative to the listed origin.)

-
-
- -

- - -5.3.5 Other Zone File Directives

- -

- - -The Master File Format was initially defined in RFC 1035 and has subsequently been extended. While the Master File Format itself is class independent all records in a Master File must be of the same class.

-

- - -Master File Directives include -$ORIGIN -, -$INCLUDE -, and -$TTL. -

-
- -
- - -5.3.5.1 The -$ORIGIN - Directive
- -

- - -Syntax: -$ORIGIN < - -domain-name - -> - -[ - -< - -comment - -> - -] -

-

- - - -$ORIGIN -sets the domain name that will be appended to any unqualified records. When a zone is first read in there is an implicit -$ORIGIN -< -zone-name -> -. - The current -$ORIGIN - is appended to the domain specified in the -$ORIGIN - argument if it is not absolute.

-

-$ORIGIN example.com
-WWW     CNAME   MAIN-SERVER
-
-

- - -is equivalent to

-

-WWW.EXAMPLE.COM CNAME MAIN-SERVER.EXAMPLE.COM.
-
-
-
- -
- - -5.3.5.2 The -$INCLUDE - Directive
- -

- - -Syntax: -$INCLUDE < - -filename - -> - -[ - -< - -origin - -> - -] [ - -< - -comment - -> - -] -

-

- - -Read and process the file -filename - as if it were included into the file at this point. If -origin - is specified the file is processed with -$ORIGIN -set to that value, otherwise the current -$ORIGIN - is used.

-

- - - -NOTE: -The behavior when -origin - is specified differs from that described in RFC 1035. The origin and current domain revert to the values they were prior to the -$INCLUDE - once the file has been read.

-
-
- -
- - -5.3.5.3 The -$TTL - Directive
- -

- - -Syntax: -$TTL < - -default-ttl - -> - -[ - -< - -comment - -> - -] -

-

- - -Set the default Time To Live (TTL) for subsequent records with undefined TTLs. Valid TTLs are of the range 0-2147483647 seconds.

-

- - - -$TTL - is defined in RFC 2308.

-
-
-
- -

- - -5.3.6 BIND Master File Extension: the -$GENERATE - Directive

- -
 
-$GENERATE
-
-

- - -Syntax: -$GENERATE < - -range - -> < - -lhs - -> < - -type - -> < - -rhs - -> - -[ - -< - -comment - -> - -] -

-

- - - -$GENERATE - is used to create a series of resource records that only differ from each other by an iterator. -$GENERATE -can be used to easily generate the sets of records required to support sub /24 reverse delegations described in RFC 2317: Classless IN-ADDR.ARPA delegation.

-

-$ORIGIN 0.0.192.IN-ADDR.ARPA.
-$GENERATE 1-2 0 NS SERVER$.EXAMPLE.
-$GENERATE 1-127 $ CNAME $.0
-
-

- - -is equivalent to

-

-0.0.0.192.IN-ADDR.ARPA NS SERVER1.EXAMPLE.
-0.0.0.192.IN-ADDR.ARPA NS SERVER2.EXAMPLE.
-1.0.0.192.IN-ADDR.ARPA CNAME 1.0.0.0.192.IN-ADDR.ARPA
-2.0.0.192.IN-ADDR.ARPA CNAME 2.0.0.0.192.IN-ADDR.ARPA
-...
-127.0.0.192.IN-ADDR.ARPA CNAME 127.0.0.0.192.IN-ADDR.ARPA
-.
-
-

- - - - - 

- - - - - - - - - - - - - - - - - -
-

- - - -range -

-		 -

- - -This can be one of two forms: start-stop or start-stop/step. If the first form is used then step is set to 1. All of start, stop and step must be positive.

-
-

- - - -lhs -

-		 -

- - - -lhs - describes the owner name of the resource records to be created. Any single -$ - symbols within the -lhs - side are replaced by the iterator value. To get a $ in the output use a double -$ -, e.g. -$$ -. If the -lhs - is not absolute, the current -$ORIGIN -is appended to the name.

-
-

- - - -type -

-		 -

- - -At present the only supported types are PTR, CNAME and NS.

-
-

- - - -rhs -

-		 -

- - -rhs is a domain name. It is processed similarly to lhs.

-
-

- - -The -$GENERATE - directive is a BIND extension and not part of the standard zone file format. -It is not yet implemented in BINDv9. -

-
-
- -

- - -5.3.7 Signals

- -

- - -Certain UNIX signals cause the name server to take specific actions, as described in the following table. These signals can be sent using the -kill - command.

-

- - - 

- - - - - - - - - - - - - - - - - -
-

- - - -SIGHUP -

-		 -

- - -Causes the server to read -named.conf - and reload the database.

-
-

- - - -SIGTERM -

-		 -

- - -Causes the server to clean up and exit.

-
-

- - - -SIGINT -

-		 -

- - -Causes the server to clean up and exit.

-
-

- - - -SIGQUIT -

-		 -

- - -Causes the server to clean up and exit.

-
-
-
- diff --git a/doc/arm/Bv9ARM.6.html b/doc/arm/Bv9ARM.6.html index d73c4629e9..408477e37d 100644 --- a/doc/arm/Bv9ARM.6.html +++ b/doc/arm/Bv9ARM.6.html @@ -1,236 +1,6369 @@ - - - - - Section 6. Security Considerations + Section 6. BIND 9 Configuration Reference

- -Section 6. Security Considerations

+ +Section 6. BIND 9 Configuration Reference +

+ + +BIND 9 configuration is broadly similar to BIND 8.x; however, there are a few new areas of configuration, such as views. BIND 8.x configuration files should work with few alterations in BIND 9, although more complex configurations should be reviewed to check if they can be more efficiently implemented using the new features found in BIND 9.

+

+ + +BIND 4 configuration files can be converted to the new format using the shell script
+ +contrib/named-bootconf/named-bootconf.sh +.

- - -6.1 - -Access Control Lists

+ + +6.1 + +Configuration File Elements

- - -Access Control Lists (ACLs), are address match lists that you can set up and nickname for future use in + + +Following is a list of elements used throughout the BIND configuration file documentation:

+

+ + + 

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+
+ + + +acl_name +
+		 +

+ + +The name of an +address_match_list + as defined by the +acl + statement.

+
+
+ + + +address_match_list +
+		 +

+ + +A list of one or more +ip_addr + +, + +ip_prefix + +, + +key_id + +, +or +acl_name + elements, as described in +Address Match Lists +.

+
+
+ + + +domain_name +
+		 +

+ + +A quoted string which will be used as a DNS name, for example " +my.test.domain +".

+
+
+ + + +dotted_decimal +
+		 +

+ + +One or more integers valued 0 through 255 separated only by dots (`.'), such as +123 +, +45.67 + or +89.123.45.67 +.

+
+
+ + + +ip4_addr +
+		 +

+ + +An IPv4 address with exactly four elements in +dotted_decimal + notation.

+
+
+ + + +ip6_addr +
+		 +

+ + +An IPv6 address, such as +fe80::200:f8ff:fe01:9742 +.

+
+
+ + + +ip_addr +
+		 +

+ + +An +ip4_addr + or + + +ip6_addr +.

+
+
+ + + +ip_port +
+		 +

+ + +An IP port +number +. +number + is limited to 0 through 65535, with values below 1024 typically restricted to root-owned processes. In some cases an asterisk (`*') character can be used as a placeholder to select a random high-numbered port.

+
+
+ + + +ip_prefix +
+		 +

+ + +An IP network specified as an +ip_addr +, followed by a slash (`/') and then the number of bits in the netmask. For example, +127/8 + is the network +127.0.0.0 + with netmask +255.0.0.0 + and +1.2.3.0/28 + is network +1.2.3.0 + with netmask +255.255.255.240 +.

+
+
+ + + +key_name +
+		 +

+ + +A +domain_name + representing the name of a shared key, to be used for transaction security.

+
+
+ + + +number +
+		 +

+ + +A non-negative integer with an entire range limited by the range of a C language signed integer (2,147,483,647 on a machine with 32 bit integers). Its acceptable value might further be limited by the context in which it is used.

+
+
+ + + +path_name +
+		 +

+ + +A quoted string which will be used as a pathname, such as +" + +zones/master/my.test.domain + +" +.

+
+
+ + + +size_spec +
+		 +

+ + +A number, the word +unlimited +, or the word +default +.

+

+ + +The maximum value of +size_spec + is that of unsigned long integers on the machine. An +unlimited + +size_spec + requests unlimited use, or the maximum available amount. A +default size_spec + uses the limit that was in force when the server was started.

+

+ + +A +number + can optionally be followed by a scaling factor: +K + or +k + + +for kilobytes, +M + or +m + for megabytes, and +G + or +g + for gigabytes, which scale by 1024, 1024*1024, and 1024*1024*1024 respectively.

+

+ + +Integer storage overflow is currently silently ignored during conversion of scaled values, resulting in values less than intended, possibly even negative. Using +unlimited + is the best way to safely set a really large number.

+
+
+ + + +yes_or_no +
+		 +

+ + +Either +yes + or +no +. The words +true + and +false + are also accepted, as are the numbers +1 + and +0 +.

+
+
+ +

+ + +6.1.1 + +Address Match Lists

+ +
+ +
+ + +6.1.1.1 Syntax
+ + +address_match_list = address_match_list_element ;
+ [ address_match_list_element; ... ]
+address_match_list_element = [ ! ] (ip_address [/length] |
+ key key_id | acl_name | { address_match_list } ) + +
+
+ +
+ + +6.1.1.2 Definition and Usage
+ +

+ + +Address match lists are primarily used to determine access control for various server operations. They are also used to define priorities for querying other nameservers and to set the addresses on which +named + will listen for queries. The elements which constitute an address match list can be any of the following:

+
    +
  • + + +an IP address (IPv4 or IPv6)
    • +
  • + + +an IP prefix (in the `/'-notation)
    • +
  • + + +a key ID, as defined by the key statement
    • +
  • + + +the name of an address match list previously defined with the +acl + statement
    • +
  • + + +a nested address match list enclosed in braces
    • +
+

+ + +Elements can be negated with a leading exclamation mark (`!') and the match list names "any," "none," "localhost" and "localnets" are predefined. More information on those names can be found in the description of the acl statement.

+

+ + +The addition of the key clause made the name of this syntactic element something of a misnomer, since security keys can be used to validate access without regard to a host or network address. Nonetheless, the term "address match list" is still used throughout the documentation.

+

+ + +When a given IP address or prefix is compared to an address match list, the list is traversed in order until an element matches. The interpretation of a match depends on whether the list is being used for access control, defining listen-on ports, or as a topology, and whether the element was negated.

+

+ + +When used as an access control list, a non-negated match allows access and a negated match denies access. If there is no match, access is denied. The clauses allow-query , -allow-recursion -, -blackhole -, allow-transfer -, etc.

-

- - -Using ACLs allows you to have finer control over who can access your nameserver, without cluttering up your config files with huge lists of IP addresses.

-

- - -It is a -good idea - to use ACLs, and to control access to your server. Limiting access to your server by outside parties can help prevent spoofing and DoS attacks against your server.

-

- - -Here is an example of how to properly apply ACLs:

-

- - -// Set up an ACL named "bogusnets" that will block RFC1918 space,
-// which is commonly used in spoofing attacks.

-

-acl bogusnets { 0.0.0.0/8; 1.0.0.0/8; 2.0.0.0/8; 192.0.2.0/24;
- 224.0.0.0/3; 10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16; };
-
-

- +, +allow-update + and +blackhole + all use address match lists this. Similarly, the listen-on option will cause the server to not accept queries on any of the machine's addresses which do not match the list.

+

+ -// Set up an ACL called our-nets. Replace this with the real IP numbers.

-

-acl our-nets { x.x.x.x/24; x.x.x.x/21; };
-

-options {
-
-  ...
-  ...
-
-  allow-query { our-nets; };
-  allow-recursion { our-nets; };
-  ...
-
-  blackhole { bogusnets; };
-  ...
-
-};
-
-

-zone "example.com" {
-  type master;
-  file "m/example.com";
-  allow-query { any; };
-};
-
+When used with the topology clause, a non-negated match returns a distance based on its position on the list (the closer the match is to the start of the list, the shorter the distance is between it and the server). A negated match will be assigned the maximum distance from the server. If there is no match, the address will get a distance which is further than any non-negated list element, and closer than any negated element.

+

+ + +Because of the first-match aspect of the algorithm, an element that defines a subset of another element in the list should come before the broader element, regardless of whether either is negated. For example, in
+ +1.2.3/24; ! 1.2.3.13; + the 1.2.3.13 element is completely useless because the algorithm will match any lookup for 1.2.3.13 to the 1.2.3/24 element. Using +! 1.2.3.13; 1.2.3/24 + fixes that problem by having 1.2.3.13 blocked by the negation but all other 1.2.3.* hosts fall through.

+
+
+
+ +

+ + +6.1.2 Comment Syntax

+

- - -This allows recursive queries of the server from the outside unless recursion has been previously disabled.

+ + +The BIND 9 comment syntax allows for comments to appear anywhere that white space may appear in a BIND configuration file. To appeal to programmers of all kinds, they can be written in C, C++, or shell/perl constructs.

+
+ +
+ + +6.1.2.1 Syntax
+ +

+ + +/* This is a BIND comment as in C */
+// This is a BIND comment as in C++
+# This is a BIND comment as in common UNIX shells and perl

+
+
+ +
+ + +6.1.2.2 Definition and Usage
+ +

+ + +Comments may appear anywhere that whitespace may appear in a BIND configuration file.

+

+ + +C-style comments start with the two characters /* (slash, star) and end with */ (star, slash). Because they are completely delimited with these characters, they can be used to comment only a portion of a line or to span multiple lines.

+

+ + +C-style comments cannot be nested. For example, the following is not valid because the entire comment ends with the first */:

+

+ + +/* This is the start of a comment.
+ This is still part of the comment.
+/* This is an incorrect attempt at nesting a comment. */
+ This is no longer in any comment. */

+

+ + +C++-style comments start with the two characters // (slash, slash) and continue to the end of the physical line. They cannot be continued across multiple physical lines; to have one logical comment span multiple lines, each line must use the // pair.

+

+ + +For example:

+

+ + +// This is the start of a comment. The next line
+// is a new comment, even though it is logically
+// part of the previous comment.

+

+ + +Shell-style (or perl-style, if you prefer) comments start with the character # (number sign) and continue to the end of the physical line, as in C++ comments.

+

+ + +For example:

+

+ + +# This is the start of a comment. The next line
+# is a new comment, even though it is logically
+# part of the previous comment.

+

+ + +WARNING: you cannot use the semicolon (`;') character to start a comment such as you would in a zone file. The semicolon indicates the end of a configuration statement.

+
+
+
+
+ +

+ + +6.2 + +Configuration File Grammar

+

- - -For more information on how to use ACLs to protect your server, see the -AUSCERT - advisory at
- -ftp://ftp.auscert.org.au/pub/auscert/advisory/AL-1999.004.dns_dos + + +A BIND 9 configuration consists of statements and comments. Statements end with a semicolon. Statements and comments are the only elements that can appear without enclosing braces. Many statements contain a block of substatements, which are also terminated with a semicolon.

+

+ + +The following statements are supported:

+

+ + + 

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + + +acl +

+		 +

+ + +defines a named IP address matching list, for access control and other uses.

+
+

+ + + +controls +

+		 +

+ + +declares control channels to be used by the +rndc + utility.

+
+

+ + + +include +

+		 +

+ + +includes a file.

+
+

+ + + +key +

+		 +

+ + +specifies key information for use in authentication and authorization using TSIG.

+
+

+ + + +logging +

+		 +

+ + +specifies what the server logs, and where the log messages are sent.

+
+

+ + + +options +

+		 +

+ + +controls global server configuration options and sets defaults for other statements.

+
+

+ + + +server +

+		 +

+ + +sets certain configuration options on a per-server basis.

+
+

+ + + +trusted-keys +

+		 +

+ + +defines trusted DNSSEC keys.

+
+

+ + + +view +

+		 +

+ + +defines a view.

+
+

+ + + +zone +

+		 +

+ + +defines a zone.

+
+

+ + +The +logging + and +options + statements may only occur once per configuration.

+
+ +

+ + +6.2.1 +acl Statement Grammar

+

+acl acl-name { 
+    address_match_list 
+};
+
+
+
+ +

+ + +6.2.2 +acl + + + Statement Definition and Usage

+ +

+ + +The +acl + statement assigns a symbolic name to an address match list. It gets its name from a primary use of address match lists: Access Control Lists (ACLs).

+

+ + +Note that an address match list's name must be defined with +acl + before it can be used elsewhere; no forward references are allowed.

+

+ + +The following ACLs are built-in:

+

+ + + 

+ + + + + + + + + + + + + + + + + +
+

+ + + +any +

+		 +

+ + +Matches all hosts.

+
+

+ + + +none +

+		 +

+ + +Matches no hosts.

+
+

+ + + +localhost +

+		 +

+ + +Matches the IP addresses of all interfaces on the system.

+
+

+ + + +localnets +

+		 +

+ + +Matches any host on a network for which the system has an interface.

+
+
+
+ +

+ + +6.2.3 +controls + Statement Grammar

+ +

+controls {
+   [ inet (ip_addr|*) port ip_port allow { address_match_list } ;
+         [ inet...;[...]]]
+   [ unix string permission number owner number group number ;
+         [ unix...;[..]]]
+};
+
+
+
+ +

+ + +6.2.4 +controls + Statement Definition and Usage

+ +

+ + +The +controls + statement declares control channels to be used by system administrators to affect the operation of the local nameserver. These control channels are used by the +ndc + utility to send commands to and retrieve non-DNS results from a nameserver.

+

+ + +A UNIX control channel is a "first in first out" (FIFO) named pipe in the file system, and access to it is controlled by normal file system permissions. It is created by +named + with the specified file mode bits (see the +chmod(1) + manual page), user and group owner. Note that, unlike +chmod +, the mode bits specified for +permission + will normally have a leading +0 + so the number is interpreted as octal. Also note that the user and group ownership specified as owner and group must be given as numbers, not names. It is recommended that the permissions be restricted to administrative personnel only to prevent random users on the system from having the ability to manage the local nameserver.

+

+ + +An +inet + control channel is a TCP/IP socket accessible to the Internet, created at the specified +ip_port + on the specified +ip_addr +. It is recommended that 127.0.0.1 be the only +ip_addr + used, and this only if you trust all non-privileged users on the local host to manage your nameserver.

+

+ + + +The + +controls + + statement is not yet implemented in BIND 9. The server always listens for control connections on IP address 127.0.0.1, port 953.

-

- - -6.2 -chroot - and -setuid - (for UNIX servers)

- -

- - -On UNIX servers, it is possible to run BIND in a -chrooted - environment ( -chroot() -) by specifying the ' --t -' option. This can help improve system security by placing BIND in a "sandbox," which will limit the damage done if a server is compromised.

-

- +

+ + +6.2.5 +include + Statement Grammar

+ +

+ -Another useful feature in the UNIX version of BIND is the ability to run the daemon as a nonprivileged user ( --u - < -user -> ). We suggest running as a nonprivileged user when using the -chroot - feature.

-

- -Here is an example command line to load BIND in a -chroot() - sandbox,
-/var/named -, and to run -named - -setuid - to user 202:

-

-/usr/local/bin/named -u 202 -t /var/named
-
-
- -

- - -6.2.1 The -chroot - Environment

- -

- - -In order for a -chroot() - environment to work properly in a particular directory (for example, -/var/named -), you will need to set up an environment that includes everything BIND needs to run. From BIND's point of view, -/var/named - is the root of the filesystem. You will need -/dev/null -, and any library directories and files that BIND needs to run on your system. Please consult your operating system's instructions if you need help figuring out which library files you need to copy over to the -chroot() - sandbox.

-

- - -If you are running an operating system that supports static binaries, you can also compile BIND statically and avoid the need to copy system libraries over to your -chroot() - sandbox.

+include + +filename + +; +

- + -6.2.2 Using the -setuid - Function

+6.2.6 +include + Statement Definition and Usage

- + -Prior to running the +The +include + statement inserts the specified file at the point that the +include + statement is encountered. The +include + statement facilitates the administration of configuration files by permitting the reading or writing of some things but not others. For example, the statement could include private keys that are readable only by a nameserver.

+
+
+ +

+ + +6.2.7 +key + Statement Grammar

+ +

+ + +key key_id {
 + algorithm string;
 + secret string;
+}; +

+
+
+ +

+ + +6.2.8 +key + Statement Definition and Usage

+ +

+ + +The +key + statement defines a shared secret key for use with TSIG. See +TSIG +.

+

+ + +The +key_id +, also known as the key name, is a domain name uniquely identifying the key. It can be used in a "server" statement to cause requests sent to that server to be signed with this key, or in address match lists to verify that incoming requests have been signed with a key matching this name, algorithm, and secret.

+

+ + +The +algorithm_id + is a string that specifies a security/authentication algorithm. The only algorithm currently supported with TSIG authentication is +hmac-md5 +. The +secret_string + is the secret to be used by the algorithm, and is treated as a base-64 encoded string.

+
+
+ +

+ + +6.2.9 +logging + Statement Grammar

+ +

+logging {
+   [ channel channel_name {
+     ( file path name
+         [ versions ( number | unlimited ) ]
+         [ size size spec ]
+       | syslog ( syslog_facility 
+       | null );
+     [ severity (critical | error | warning | notice |
+                 info | debug [ level ] | dynamic ; ]
+     [ print-category yes or no;
+     [ print-severity yes or no; ]
+     [ print-time yes or no; ]
+   }; ]
+   [ category category_name {
+     channel_name ; [ channel_name ; ... ]
+   }; ] 
+    ...
+};
+
+ +
+
+ +

+ + +6.2.10 +logging + Statement Definition and Usage

+ +

+ + +The +logging + statement configures a wide variety of logging options for the nameserver. Its +channel + phrase associates output methods, format options and severity levels with a name that can then be used with the +category + phrase to select how various classes of messages are logged.

+

+ + +Only one +logging + statement is used to define as many channels and categories as are wanted. If there is no +logging + statement, the logging configuration will be:

+
+
+logging {
+     category "default" { "default_syslog"; "default_debug"; };
+  };
+
+
+

+ + +In BIND 9, the logging configuration is only established when the entire configuration file has been parsed. In BIND 8, it was established as soon as the +logging + statement was parsed. When the server is starting up, all logging messages regarding syntax errors in the configuration file go to the default channels, or to standard error if the " +-g +" option was specified.

+
+ +
+ + +6.2.10.1 The +channel + Phrase
+ +

+ + +All log output goes to one or more +channels +; you can make as many of them as you want.

+

+ + +Every channel definition must include a clause that says whether messages selected for the channel go to a file, to a particular syslog facility, or are discarded. It can optionally also limit the message severity level that will be accepted by the channel (the default is +info +), and whether to include a named - daemon, use the -touch - utility (to change file access and modification times) or the -chown - utility (to set the user id and/or group id) on files to which you want BIND to write.

+-generated time stamp, the category name and/or severity level (the default is not to include any).

+

+ + +The word +null + as the destination option for the channel will cause all messages sent to it to be discarded; in that case, other options for the channel are meaningless.

+

+ + +The +file + clause can include limitations both on how large the file is allowed to become, and how many versions of the file will be saved each time the file is opened.

+

+ + +The +size + option for files is simply a hard ceiling on log growth. If the file ever exceeds the size, then +named + will not write anything more to it until the file is reopened; exceeding the size does not automatically trigger a reopen. The default behavior is not to limit the size of the file.

+

+ + +If you use the +version + log file option, then +named + will retain that many backup versions of the file by renaming them when opening. For example, if you choose to keep 3 old versions of the file +lamers.log + then just before it is opened +lamers.log.1 + is renamed to +lamers.log.2 +, +lamers.log.0 + is renamed to +lamers.log.1 +, and +lamers.log + is renamed to +lamers.log.0 +. No rolled versions are kept by default; any existing log file is simply appended. The +unlimited + keyword is synonymous with +99 + in current BIND releases.

+

+ + +Example usage of the size and versions options:

+ +
+    channel "an_example_channel" {
+        file "example.log" versions 3 size 20m;
+        print-time yes;
+        print-category yes;
+    };
+
+ +

+ + +The argument for the +syslog + clause is a syslog facility as described in the +syslog + man page. How +syslog + will handle messages sent to this facility is described in the +syslog.conf + man page. If you have a system which uses a very old version of +syslog + that only uses two arguments to the +openlog() + function, then this clause is silently ignored.

+

+ + +The +severity + clause works like +syslog +'s "priorities," except that they can also be used if you are writing straight to a file rather than using +syslog +. Messages which are not at least of the severity level given will not be selected for the channel; messages of higher severity levels will be accepted.

+

+ + +If you are using +syslog +, then the +syslog.conf + priorities will also determine what eventually passes through. For example, defining a channel facility and severity as +daemon + and +debug + but only logging +daemon.warning + via +syslog.conf + will cause messages of severity +info + and +notice + to be dropped. If the situation were reversed, with +named + writing messages of only +warning + or higher, then +syslogd + would print all messages it received from the channel.

+

+ + +The server can supply extensive debugging information when it is in debugging mode. If the server's global debug level is greater than zero, then debugging mode will be active. The global debug level is set either by starting the +named + server with the " +-d +" flag followed by a positive integer, or by running +rndc trace + ( +the latter method is not yet implemented +). The global debug level can be set to zero, and debugging mode turned off, by running +ndc notrace +. All debugging messages in the server have a debug level, and higher debug levels give more detailed output. Channels that specify a specific debug severity, for example:

+ +
+
+  channel "specific_debug_level" {
+      file "foo";
+      severity debug 3;
+  };
+
+ +

+ + +will get debugging output of level 3 or less any time the server is in debugging mode, regardless of the global debugging level. Channels with +dynamic + severity use the server's global level to determine what messages to print.

+

+ + +If +print-time + has been turned on, then the date and time will be logged. +print-time + may be specified for a +syslog + channel, but is usually pointless since +syslog + also prints the date and time. If +print-category + is requested, then the category of the message will be logged as well. Finally, if +print-severity + is on, then the severity level of the message will be logged. The +print- + options may be used in any combination, and will always be printed in the following order: time, category, severity. Here is an example where all three +print- + options are on:

+
+
+ + + +28-Feb-2000 15:05:32.863 general: notice: running +
+

+ + +There are four predefined channels that are used for +named +'s default logging as follows. How they are used is described in +the category Phrase +.

+
+
+
+    channel "default_syslog" {
+        syslog daemon;				// end to syslog's daemon
+						// facility
+        severity info;				// only send priority info
+						// and higher
+    };
+    channel "default_debug" {
+        file "named.run";			// write to named.run in
+						// the working directory
+						// Note: stderr is used instead
+						// of "named.run"
+						// if the server is started
+						// with the '-f' option.
+        severity dynamic			// log at the server's
+						// current debug level
+    };
+    channel "default_stderr" {			// writes to stderr
+        file "<stderr>";			// this is illustrative only;
+						// there's currently no way of
+						// specifying an internal file
+						// descriptor in the 
+						// configuration language.
+        severity info;				// only send priority info
+						// and higher
+    };
+    channel "null" {
+       null;					// toss anything sent to
+						// this channel
+    };
+
+
+

+ + +The +default_debug + channel normally writes to a file +named.run + in the server's working directory. For security reasons, when the " +-u +" command line option is used, the +named.run + file is created only after +named + has changed to the new UID, and any debug output generated while +named + is starting up and still running as root is discarded. If you need to capture this output, you must run the server with the " +-g +" option and redirect standard error to a file.

+

+ + +Once a channel is defined, it cannot be redefined. Thus you cannot alter the built-in channels directly, but you can modify the default logging by pointing categories at channels you have defined.

+
+
+
+ +
+ + +6.2.10.2 + +The +category + Phrase
+ +

+ + +There are many categories, so you can send the logs you want to see wherever you want, without seeing logs you don't want. If you don't specify a list of channels for a category, then log messages in that category will be sent to the +default + category instead. If you don't specify a default category, the following "default default" is used:

+
+category "default" { "default_syslog"; "default_debug"; };
+
+
+

+ + +As an example, let's say you want to log security events to a file, but you also want keep the default logging behavior. You'd specify the following:

+
+
+channel "my_security_channel" {
+    file "my_security_file";
+    severity info;
+};
+category "security" {
+    "my_security_channel";
+    "default_syslog";
+    "default_debug";
+};
+
+
+

+ + +To discard all messages in a category, specify the null channel:

+
+
+category "xfer-out" { "null"; };
+category "notify" { "null"; };
+
+
+

+ + +Following are the available categories and brief descriptions of the types of log information they contain +. +More categories may be added in future BIND releases. + +

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + + +default +

+		 +

+ + +The default category defines the logging options for those categories where no specific configuration has been defined.

+
+

+ + + +general +

+		 +

+ + +The catch-all. Many things still aren't classified into categories, and they all end up here.

+
+

+ + + +database +

+		 +

+ + +Messages relating to the databases used internally by the name server to store zone and cache data.

+
+

+ + + +security +

+		 +

+ + +Approval and denial of requests.

+
+

+ + + +config +

+		 +

+ + +Configuration file parsing and processing.

+
+

+ + + +resolver +

+		 +

+ + +DNS resolution, such as the recursive lookups performed on behalf of clients by a caching name server.

+
+

+ + + +xfer-in +

+		 +

+ + +Zone transfers the server is receiving.

+
+

+ + + +xfer-out +

+		 +

+ + +Zone transfers the server is sending.

+
+

+ + + +notify +

+		 +

+ + +The NOTIFY protocol.

+
+

+ + + +client +

+		 +

+ + +Processing of client requests.

+
+

+ + + +network +

+		 +

+ + +Network operations.

+
+

+ + + +update +

+		 +

+ + +Dynamic updates.

+
+
+
+
+ +

+ + +6.2.11 +options + Statement Grammar

+ +

+ + +This is the grammar of the +option + statement in the +named.conf + file:

+

+options {
+
+    [ version version_string; ]
+    [ directory path_name; ]
+    [ named-xfer path_name; ]
+    [ tkey-domain domainname; ]
+    [ tkey-dhkey keyname keyid; ]
+    [ dump-file path_name; ]
+    [ memstatistics-file path_name; ]
+    [ pid-file path_name; ]
+    [ statistics-file path_name; ]
+    [ auth-nxdomain yes_or_no; ]
+    [ deallocate-on-exit yes_or_no; ]
+    [ dialup yes_or_no; ]
+    [ fake-iquery yes_or_no; ]
+    [ fetch-glue yes_or_no; ]
+    [ has-old-clients yes_or_no; ]
+    [ host-statistics yes_or_no; ]
+    [ multiple-cnames yes_or_no; ]
+    [ notify yes_or_no; ]
+    [ recursion yes_or_no; ]
+    [ rfc2308-type1 yes_or_no; ]
+    [ use-id-pool yes_or_no; ]
+    [ maintain-ixfr-base yes_or_no; ]
+    [ forward ( only | first ); ]
+    [ forwarders { [ in_addr ; [ in_addr ; ... ] ] }; ]
+    [ check-names ( master | slave | response )( warn | fail | ignore ); ]
+    [ allow-query { address_match_list }; ]
+    [ allow-transfer { address_match_list }; ]
+    [ allow-recursion { address_match_list }; ]
+    [ blackhole { address_match_list  };  ]
+    [ listen-on [ port ip_port ] { address_match_list }; ]
+    [ query-source [ address ( ip_addr | * ) ] [ port ( ip_port | * ) ]; ]
+    [ max-transfer-time-in number; ]
+    [ max-transfer-time-out number; ]
+    [ max-transfer-idle-in number; ]
+    [ max-transfer-idle-out number; ]
+    [ tcp-clients number; ]
+    [ recursive-clients number; ]
+    [ serial-queries number; ]
+    [ transfer-format ( one-answer | many-answers ); ]
+    [ transfers-in  number; ]
+    [ transfers-out number; ]
+    [ transfers-per-ns number; ]
+    [ transfer-source ip4_addr; ]
+    [ transfer-source-v6 ip6_addr; ]
+    [ also-notify { ip_addr; [ ip_addr; ... ] }; ]
+    [ max-ixfr-log-size number; ]    [ coresize size_spec ; ]    [ datasize size_spec ; ]    [ files size_spec ; ]    [ stacksize size_spec ; ]    [ cleaning-interval number; ]    [ heartbeat-interval number; ]    [ interface-interval number; ]    [ statistics-interval number; ]
+    [ topology { address_match_list }; ]
+    [ sortlist { address_match_list }; ]
+    [ rrset-order { order_spec ; [ order_spec ; ... ] ] };    [ lame-ttl number; ]    [ max-ncache-ttl number; ]
+    [ max-cache-ttl number; ]
+    [ sig-validity-interval number ; ]
+    [ min-roots number; ]
+    [ use-ixfr yes_or_no ; ]
+    [ treat-cr-as-space yes_or_no ; ]
+};
+
+
+
+ +

+ + +6.2.12 +options + Statement Definition and Usage

+ +

+ + +The +options + statement sets up global options to be used by BIND. This statement may appear only once in a configuration file. If more than one occurrence is found, the first occurrence determines the actual options used, and a warning will be generated. If there is no +options + statement, an options block with each option set to its default will be used.

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + + +version +

+		 +

+ + +The version the server should report via a query of name +version.bind + in class +chaos +. The default is the real version number of this server.

+
+

+ + + +directory +

+		 +

+ + +The working directory of the server. Any non-absolute pathnames in the configuration file will be taken as relative to this directory. The default location for most server output files (e.g. +named.run +) is this directory. If a directory is not specified, the working directory defaults to ` +. +', the directory from which the server was started. The directory specified should be an absolute path.

+
+

+ + + +named-xfer +

+		 +

+ + + +This option is obsolete. + It was used in BIND 8 to specify the pathname to the +named-xfer + program. In BIND 9, no separate +named-xfer + program is needed; its functionality is built into the name server.

+
+

+ + + +tkey-domain +

+		 +

+ + +The domain appended to the names of all shared keys generated with +TKEY +. When a client requests a +TKEY + exchange, it may or may not specify the desired name for the key. If present, the name of the shared key will be " +client specified part +" + " +tkey-domain +". Otherwise, the name of the shared key will be " +random hex digits +" + " +tkey-domain +". In most cases, the +domainname + should be the server's domain name.

+
+

+ + + +tkey-dhkey +

+		 +

+ + +The Diffie-Hellman key used by the server to generate shared keys with clients using the Diffie-Hellman mode of +TKEY +. The server must be able to load the public and private keys from files in the working directory. In most cases, the keyname should be the server's host name.

+
+

+ + + +dump-file +

+		 +

+ + +The pathname of the file the server dumps the database to when it receives +SIGINT + signal ( +ndc dumpdb +). If not specified, the default is +named_dump.db +. +Not yet implemented in BIND 9. +

+
+

+ + + +memstatistics-file +

+		 +

+ + +The pathname of the file the server writes memory usage statistics to on exit. If not specified, the default is +named.memstats +. +Not yet implemented in BIND 9. +

+
+

+ + + +pid-file +

+		 +

+ + +The pathname of the file the server writes its process ID in. If not specified, the default is operating system dependent, but is usually
+ +/var/run/named.pid + or +/etc/named.pid +. The pid-file is used by programs that want to send signals to the running nameserver.

+
+

+ + + +statistics-file +

+		 +

+ + +The pathname of the file the server appends statistics to. If not specified, the default is +named.stats +. +Not yet implemented in BIND 9 +.

+
+
+ +
+ + +6.2.12.1 + +Boolean Options
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + + +auth-nxdomain +

+		 +

+ + +If +yes +, then the +AA + bit is always set on NXDOMAIN responses, even if the server is not actually authoritative. The default is +no +; this is a change from BIND 8. If you are using very old DNS software, you may need to set it to +yes +.

+
+

+ + + +deallocate-on-exit +

+		 +

+ + +This option was used in BIND 8 to enable checking for memory leaks on exit. BIND 9 ignores the option and always performs the checks.

+
+

+ + + +dialup +

+		 +

+ + +If +yes +, then the server treats all zones as if they are doing zone transfers across a dial on demand dialup link, which can be brought up by traffic originating from this server. This has different effects according to zone type and concentrates the zone maintenance so that it all happens in a short interval, once every +heartbeat-interval + and hopefully during the one call. It also suppresses some of the normal zone maintenance traffic. The default is +no +.

+

+ + +The +dialup + option may also be specified in the +zone + statement, in which case it overrides the +options dialup +statement.

+

+ + +If the zone is a master then the server will send out a NOTIFY request to all the slaves. This will trigger the zone serial number check in the slave (providing it supports NOTIFY) allowing the slave to verify the zone while the connection is active.

+

+ + +If the zone is a slave or stub then the server will suppress the regular "zone up to date" queries and only perform them when the
+ +heartbeat-interval + expires. +Not yet implemented in BIND 9. +

+
+

+ + + +fake-iquery +

+		 +

+ + +In BIND 8, this option was used to enable simulating the obsolete DNS query type IQUERY. BIND 9 never does IQUERY simulation.

+
+

+ + + +fetch-glue +

+		 +

+ + +(Information present outside of the authoritative nodes in the zone is called +glue + information). If +yes + (the default), the server will fetch glue resource records it doesn't have when constructing the additional data section of a response. +fetch-glue + +no + + +can be used in conjunction with +recursion + +no + + +to prevent the server's cache from growing or becoming corrupted (at the cost of requiring more work from the client). +Not yet implemented in BIND 9. +

+
+

+ + + +has-old-clients +

+		 +

+ + +This option was incorrectly implemented in BIND 8, and is ignored by BIND 9. To achieve the intended effect of
+ +has-old-clients + +yes +, specify the two separate options +auth-nxdomain + +yes + and +rfc2308-type1 + +no + instead.

+
+

+ + + +host-statistics +

+		 +

+ + +If +yes +, then statistics are kept for every host that the nameserver interacts with. The default is +no +. Note: turning on +host-statistics + can consume huge amounts of memory. +Not yet implemented in BIND 9. +

+
+

+ + + +maintain-ixfr-base +

+		 +

+ + + +This option is obsolete +. It was used in BIND 8 to determine whether a transaction log was kept for Incremental Zone Transfer. BIND 9 maintains a transaction log whenever possible. If you need to disable outgoing incremental zone transfers, use +provide-ixfr + +no +.

+
+

+ + + +multiple-cnames +

+		 +

+ + +This option was used in BIND 8 to allow a domain name to allow multiple CNAME records in violation of the DNS standards. BIND 9 currently does not check for multiple CNAMEs in zone data loaded from master files, but such checks may be introduced in a later release. BIND 9 always strictly enforces the CNAME rules in dynamic updates.

+
+

+ + + +notify +

+		 +

+ + +If +yes + (the default), DNS NOTIFY messages are sent when a zone the server is authoritative for changes. See + Notify +, for more information. The +notify + option may also be specified in the +zone + statement, in which case it overrides the +options notify + statement. It would only be necessary to turn off this option if it caused slaves to crash +. +

+
+

+ + + +recursion +

+		 +

+ + +If +yes +, and a DNS query requests recursion, then the server will attempt to do all the work required to answer the query. If recursion is not on, the server will return a referral to the client if it doesn't know the answer. The default is +yes +. See also +fetch-glue + above.

+
+

+ + + +rfc2308-type1 +

+		 +

+ + +Setting this to +yes + will cause the server to send NS records along with the SOA record for negative answers. The default is +no +. +Not yet implemented in BIND 9 +.

+
+

+ + + +use-id-pool +

+		 +

+ + + +This option is obsolete +. BIND 9 always allocates query IDs from a pool.

+
+

+ + + +treat-cr-as-space +

+		 +

+ + +This option was used in BIND 8 to make the server treat " +\r +" characters the same way as +<space> +" " or " +\t +", to facilitate loading of zone files on a UNIX system that were generated on an NT or DOS machine. In BIND 9, both UNIX " +\n +" and NT/DOS " +\r\n +" newlines are always accepted, and the option is ignored.

+
+ +
+
+ +
+ + +6.2.12.2 Forwarding
+ +

+ + +The forwarding facility can be used to create a large site-wide cache on a few servers, reducing traffic over links to external nameservers. It can also be used to allow queries by servers that do not have direct access to the Internet, but wish to look up exterior names anyway. Forwarding occurs only on those queries for which the server is not authoritative and does not have the answer in its cache.

+

+ + + 

+ + + + + + + + + +
+

+ + + +forward +

+		 +

+ + +This option is only meaningful if the forwarders list is not empty. A value of +first +, the default, causes the server to query the forwarders first, and if that doesn't answer the question the server will then look for the answer itself. If +only + is specified, the server will only query the forwarders.

+
+

+ + + +forwarders +

+		 +

+ + +Specifies the IP addresses to be used for forwarding. The default is the empty list (no forwarding).

+
+

+ + +Forwarding can also be configured on a per-domain basis, allowing for the global forwarding options to be overridden in a variety of ways. You can set particular domains to use different forwarders, or have a different +forward only/first + behavior, or not forward at all. See +zone Statement Grammar + for more information.

+
+
+ +
+ + +6.2.12.3 + +Name Checking
+ +

+ + +The server can check domain names based upon their expected client contexts. For example, a domain name used as a hostname can be checked for compliance with the RFCs defining valid hostnames.

+

+ + +Three checking methods are available:

+

+ + + 

+ + + + + + + + + + + + + +
+

+ + + +ignore +

+		 +

+ + +No checking is done.

+
+

+ + + +warn +

+		 +

+ + +Names are checked against their expected client contexts. Invalid names are logged, but processing continues normally.

+
+

+ + + +fail +

+		 +

+ + +Names are checked against their expected client contexts. Invalid names are logged, and the offending data is rejected.

+
+

+ + +The server can check names in three areas: master zone files, slave zone files, and in responses to queries the server has initiated. If +check-names response fail + has been specified, and answering the client's question would require sending an invalid name to the client, the server will send a REFUSED response code to the client.

+

+ + +The defaults are:

+

+    check-names master fail;
+    check-names slave warn;
+    check-names response ignore;
+

+ + + +check-names + may also be specified in the +zone + statement, in which case it overrides the +options check-names + statement. When used in a +zone + statement, the area is not specified because it can be deduced from the zone type.

+
+
+ + + +Name checking is not yet implemented in BIND 9. +
+
+
+
+ +
+ + +6.2.12.4 + +Access Control
+ +

+ + +Access to the server can be restricted based on the IP address of the requesting system. See +Address Match Lists + for details on how to specify IP address lists.

+

+ + + 

+ + + + + + + + + + + + + + + + + +
+

+ + + +allow-query +

+		 +

+ + +Specifies which hosts are allowed to ask ordinary questions. +allow-query + may also be specified in the +zone + statement, in which case it overrides the +options allow-query + statement. If not specified, the default is to allow queries from all hosts.

+
+

+ + + +allow-recursion +

+		 +

+ + +Specifies which hosts are allowed to make recursive queries through this server. If not specified, the default is to allow recursive queries from all hosts.

+
+

+ + + +allow-transfer +

+		 +

+ + +Specifies which hosts are allowed to receive zone transfers from the server. +allow-transfer + may also be specified in the +zone + statement, in which case it overrides the +options allow-transfer + statement. If not specified, the default is to allow transfers from all hosts.

+
+

+ + + +blackhole +

+		 +

+ + +Specifies a list of addresses that the server will not accept queries from or use to resolve a query. Queries from these addresses will not be responded to. The default is +none +. +Not yet implemented in BIND 9. +

+
+
+
+ +
+ + +6.2.12.5 Interfaces
+ +

+ + +The interfaces and ports that the server will answer queries from may be specified using the +listen-on + option. +listen-on + takes an optional port, and an +address_match_list +. The server will listen on all interfaces allowed by the address match list. If a port is not specified, port 53 will be used.

+

+ + +Multiple +listen-on + statements are allowed. For example,

+ +
+listen-on { 5.6.7.8; };
+listen-on port 1234 { !1.2.3.4; 1.2/16; };
+
+

+ + +will enable the nameserver on port 53 for the IP address 5.6.7.8, and on port 1234 of an address on the machine in net 1.2 that is not 1.2.3.4.

+

+ + +If no +listen-on + is specified, the server will listen on port 53 on all interfaces.

+

+ + +The +listen-on-v6 + option is used to specify the ports on which the server will listen for incoming queries sent using IPv6.

+

+ + +The server does not bind a separate socket to each IPv6 interface address as it does for IPv4. Instead, it always listens on the IPv6 wildcard address. Therefore, the only values allowed for the +address_match_list + argument to the +listen-on-v6 + statement are " +{ any; } +" and " +{ none; } +".

+

+ + +Multiple +listen-on-v6 + options can be used to listen on multiple ports:

+ +
+listen-on-v6 port 53 { any; };
+listen-on-v6 port 1234 { any; };
+
+ +

+ + +To make the server not listen on any IPv6 address, use

+ +
+listen-on-v6 { none; };
+
+ +

+ + +If no +listen-on-v6 +statement is specified, the server will listen on port 53 on the IPv6 wildcard address.

+
+
+ +
+ + +6.2.12.6 Query Address
+ +

+ + +If the server doesn't know the answer to a question, it will query other nameservers. +query-source + specifies the address and port used for such queries. For queries sent over IPv6, there is a separate +query-source-v6 + option. If +address + is +* + or is omitted, a wildcard IP address ( +INADDR_ANY +) will be used. If +port + is +* + or is omitted, a random unprivileged port will be used. The defaults are

+ +
+query-source address * port *;
+query-source-v6 address * port *
+
+ +

+ + +Note: +query-source + currently applies only to UDP queries; TCP queries always use a wildcard IP address and a random unprivileged port.

+
+
+ +
+ + +6.2.12.7 + +Zone Transfers
+ +

+ + +BIND has mechanisms in place to facilitate zone transfers and set limits on the amount of load that transfers place on the system. The following options apply to zone transfers.

+

+ + + 

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + + +also-notify +

+		 +

+ + +Defines a global list of IP addresses that are also sent NOTIFY messages whenever a fresh copy of the zone is loaded. This helps to ensure that copies of the zones will quickly converge on stealth servers. If an +also-notify + list is given in a +zone + statement, it will override the +options also-notify + statement. When a +zone notify + statement is set to +no +, the IP addresses in the global +also-notify + list will not be sent NOTIFY messages for that zone. The default is the empty list (no global notification list).

+
+

+ + + +max-transfer-time-in +

+		 +

+ + +Inbound zone transfers running longer than this many minutes will be terminated. The default is 120 minutes (2 hours).

+
+

+ + + +max-transfer-idle-in +

+		 +

+ + +Inbound zone transfers making no progress in this many minutes will be terminated. The default is 60 minutes (1 hour).

+
+

+ + + +max-transfer-time-out +

+		 +

+ + +Outbound zone transfers running longer than this many minutes will be terminated. The default is 120 minutes (2 hours).

+
+

+ + + +max-transfer-idle-out +

+		 +

+ + +Outbound zone transfers making no progress in this many minutes will be terminated. The default is 60 minutes

+

+ + +(1 hour).

+
+

+ + + +serial-queries +

+		 +

+ + +Slave servers will periodically query master servers to find out if zone serial numbers have changed. Each such query uses a minute amount of the slave server's network bandwidth, but more importantly each query uses a small amount of memory in the slave server while waiting for the master server to respond. The +serial-queries +option sets the maximum number of concurrent serial-number queries allowed to be outstanding at any given time. The default is 4. Note: If a server loads a large (tens or hundreds of thousands) number of slave zones, then this limit should be raised to the high hundreds or low thousands, otherwise the slave server may never actually become aware of zone changes in the master servers. Beware, though, that setting this limit arbitrarily high can spend a considerable amount of your slave server's network, CPU, and memory resources. As with all tunable limits, this one should be changed gently and monitored for its effects. +Not yet implemented in BIND 9. +

+
+

+ + + +transfer-format +

+		 +

+ + +The server supports two zone transfer methods. +one-answer + uses one DNS message per resource record transferred. +many-answers + packs as many resource records as possible into a message. +many-answers + is more efficient, but is only known to be understood by BIND 9, BIND 8.x and patched versions of BIND 4.9.5. The default is +many-answers +. +transfer-format + may be overridden on a per-server basis by using the +server + statement.

+
+

+ + + +transfers-in +

+		 +

+ + +The maximum number of inbound zone transfers that can be running concurrently. The default value is +10 +. Increasing +transfers-in + may speed up the convergence of slave zones, but it also may increase the load on the local system.

+
+

+ + + +transfers-out +

+		 +

+ + +The maximum number of outbound zone transfers that can be running concurrently. Zone transfer requests in excess of the limit will be refused. The default value is +10 +.

+
+

+ + + +transfers-per-ns +

+		 +

+ + +The maximum number of inbound zone transfers that can be concurrently transferring from a given remote nameserver. The default value is +2 +. Increasing +transfers-per-ns + may speed up the convergence of slave zones, but it also may increase the load on the remote nameserver. +transfers-per-ns + may be overridden on a per-server basis by using the +transfers + phrase of the +server + statement.

+
+

+ + + +transfer-source +

+		 +

+ + + +transfer-source + determines which local address will be bound to IPv4 TCP connections used to fetch zones transferred inbound by the server. If not set, it defaults to a system controlled value which will usually be the address of the interface "closest to" the remote end. This address must appear in the remote end's +allow-transfer + option for the zone being transferred, if one is specified. This statement sets the +transfer-source + for all zones, but can be overridden on a per-zone basis by including a
+ +transfer-source + statement within the +zone + block in the configuration file.

+
+

+ + + +transfer-source-v6 +

+		 +

+ + +The same as +transfer-source +, except zone transfers are performed using IPv6.

+
+
+
+ +
+ + +6.2.12.8 Resource Limits
+ +

+ + +The server's usage of many system resources can be limited. Some operating systems don't support some of the limits. On such systems, a warning will be issued if the unsupported limit is used. Some operating systems don't support limiting resources.

+

+ + +Scaled values are allowed when specifying resource limits. For example, +1G + can be used instead of +1073741824 + to specify a limit of one gigabyte. +unlimited + requests unlimited use, or the maximum available amount. +default + uses the limit that was in force when the server was started. See the description of +size_spec + in +Configuration File Elements + for more details.

+

+ + + 

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + + +coresize +

+		 +

+ + +The maximum size of a core dump. The default is +default +. +Not yet implemented in BIND 9. +

+
+

+ + + +datasize +

+		 +

+ + +The maximum amount of data memory the server may use. The default is +default +. +Not yet implemented in BIND 9. +

+
+

+ + + +files +

+		 +

+ + +The maximum number of files the server may have open concurrently. The default is +unlimited +. Note: on some operating systems the server cannot set an unlimited value and cannot determine the maximum number of open files the kernel can support. On such systems, choosing +unlimited + will cause the server to use the larger of the +rlim_max + for +RLIMIT_NOFILE + and the value returned by +sysconf(_SC_OPEN_MAX) +. If the actual kernel limit is larger than this value, use +limit files +to specify the limit explicitly. +Not yet implemented in BIND 9. +

+
+

+ + + +max-ixfr-log-size +

+		 +

+ + +The +max-ixfr-log-size + will be used in a future release of the server to limit the size of the transaction log kept for Incremental Zone Transfer. +Not yet implemented in BIND 9. +

+
+

+ + + +recursive-clients +

+		 +

+ + +The maximum number of simultaneous recursive lookups the server will perform on behalf of clients. The default is +100 +.

+
+

+ + + +stacksize +

+		 +

+ + +The maximum amount of stack memory the server may use. The default is +default +. +Not yet implemented in BIND 9. +

+
+

+ + + +tcp-clients +

+		 +

+ + +The maximum number of simultaneous client TCP connections that the server will accept. The default is +100 +.

+
+
+
+ + + +Resource limits are not yet implemented in BIND 9. +
+
+
+
+ +
+ + +6.2.12.9 Periodic Task Intervals
+ +

+ + + 

+ + + + + + + + + + + + + + + + + +
+

+ + + +cleaning-interval +

+		 +

+ + +The server will remove expired resource records from the cache every +cleaning-interval +minutes. The default is +60 + minutes. If set to +0 +, no periodic cleaning will occur.

+
+

+ + + +heartbeat-interval +

+		 +

+ + +The server will perform zone maintenance tasks for all zones marked +dialup yes + whenever this interval expires. The default is +60 + minutes. Reasonable values are up to 1 day (1440 minutes). If set to +0 +, no zone maintenance for these zones will occur. +Not yet implemented in BIND 9. +

+
+

+ + + +interface-interval +

+		 +

+ + +The server will scan the network interface list every +interface-interval + minutes. The default is +60 + minutes. If set to +0 +, interface scanning will only occur when the configuration file is loaded. After the scan, listeners will be started on any new interfaces (provided they are allowed by the +listen-on + configuration). Listeners on interfaces that have gone away will be cleaned up.

+
+

+ + + +statistics-interval +

+		 +

+ + +Nameserver statistics will be logged every +statistics-interval + minutes. The default is +60 +. If set to +0 +, no statistics will be logged. +Not yet implemented in BIND 9. +

+
+
+
+ +
+ + +6.2.12.10 + +Topology
+ +

+ + +All other things being equal, when the server chooses a nameserver to query from a list of nameservers, it prefers the one that is topologically closest to itself. The +topology + statement takes an +address_match_list + and interprets it in a special way. Each top-level list element is assigned a distance. Non-negated elements get a distance based on their position in the list, where the closer the match is to the start of the list, the shorter the distance is between it and the server. A negated match will be assigned the maximum distance from the server. If there is no match, the address will get a distance which is further than any non-negated list element, and closer than any negated element. For example,

+ +
+    topology {
+    10/8;
+    !1.2.3/24;
+    { 1.2/16; 3/8; };
+    };
+
+ +

+ + +will prefer servers on network 10 the most, followed by hosts on network 1.2.0.0 (netmask 255.255.0.0) and network 3, with the exception of hosts on network 1.2.3 (netmask 255.255.255.0), which is preferred least of all.

+

+ + +The default topology is

+ +
+    topology { localhost; localnets; };
+
+ +

+ + + +The + +topology + + option is not yet implemented in BIND 9. +

+
+
+ +
+ + +6.2.12.11 + +The +sortlist + Statement
+ +

+ + +Resource Records (RRs) are the data associated with the names in a domain name space. The data is maintained in the form of sets of RRs. The order of RRs in a set is, by default, not significant. Therefore, to control the sorting of records in a set of resource records, or +RRset +, you must use the +sortlist + statement.

+

+ + +RRs are explained more fully in +See Types of Resource Records and When to Use Them +. Specifications for RRs are documented in RFC 1035.

+

+ + +When returning multiple RRs the nameserver will normally return them in +Round Robin + + +order, that is, after each request the first RR is put at the end of the list. The client resolver code should rearrange the RRs as appropriate, that is, using any addresses on the local net in preference to other addresses. However, not all resolvers can do this or are correctly configured. When a client is using a local server the sorting can be performed in the server, based on the client's address. This only requires configuring the nameservers, not all the clients.

+

+ + +The +sortlist + statement (see below) takes an +address_match_list +and interprets it even more specifically than the +topology + statement does (see +Topology +). Each top level statement in the +sortlist + must itself be an explicit +address_match_list + with one or two elements. The first element (which may be an IP address, an IP prefix, an ACL name or a nested +address_match_list +) of each top level list is checked against the source address of the query until a match is found.

+

+ + +Once the source address of the query has been matched, if the top level statement contains only one element, the actual primitive element that matched the source address is used to select the address in the response to move to the beginning of the response. If the statement is a list of two elements, then the second element is treated the same as the +address_match_list + in a +topology + statement. Each top level element is assigned a distance and the address in the response with the minimum distance is moved to the beginning of the response.

+

+ + +In the following example, any queries received from any of the addresses of the host itself will get responses preferring addresses on any of the locally connected networks. Next most preferred are addresses on the 192.168.1/24 network, and after that either the 192.168.2/24 or
+192.168.3/24 network with no preference shown between these two networks. Queries received from a host on the 192.168.1/24 network will prefer other addresses on that network to the 192.168.2/24 and
+192.168.3/24 networks. Queries received from a host on the 192.168.4/24 or the 192.168.5/24 network will only prefer other addresses on their directly connected networks.

+ +
+sortlist {
+    { localhost;					// IF   the local host
+        { localnets;					// THEN first fit on the
+            192.168.1/24;				//   following nets
+            { 192,168.2/24; 192.168.3/24; }; }; };
+    { 192.168.1/24;					// IF   on class C 192.168.1
+        { 192.168.1/24;					// THEN use .1, or .2 or .3
+            { 192.168.2/24; 192.168.3/24; }; }; };
+    { 192.168.2/24;					// IF   on class C 192.168.2
+        { 192.168.2/24;					// THEN use .2, or .1 or .3
+            { 192.168.1/24; 192.168.3/24; }; }; };
+    { 192.168.3/24;					// IF   on class C 192.168.3
+        { 192.168.3/24;					// THEN use .3, or .1 or .2
+            { 192.168.1/24; 192.168.2/24; }; }; };
+    { { 192.168.4/24; 192.168.5/24; };
+							// if .4 or .5, prefer that net
+    };
+};
+
+ +

+ + +The following example will give reasonable behavior for the local host and hosts on directly connected networks. It is similar to the behavior of the address sort in BIND 8.x. Responses sent to queries from the local host will favor any of the directly connected networks. Responses sent to queries from any other hosts on a directly connected network will prefer addresses on that same network. Responses to other queries will not be sorted.

+ +
+sortlist {
+           { localhost; localnets; };
+           { localnets; };
+};
+
+ +

+ + + +The + +sortlist + + option is not yet implemented in BIND 9. +

+
+
+ +
+ + +6.2.12.12 + +RRset Ordering
+ +

+ + +When multiple records are returned in an answer it may be useful to configure the order of the records placed into the response. For example, the records for a zone might be configured always to be returned in the order they are defined in the zone file. Or perhaps a random shuffle of the records as they are returned is wanted. The +rrset-order + statement permits configuration of the ordering made of the records in a multiple record response. The default, if no ordering is defined, is a cyclic ordering (round robin).

+

+ + +An +order_spec + is defined as follows:

+ +
+[ class class_name  ][ type type_name ][ name "domain_name"]
+     order ordering
+
+

+ + +If no class is specified, the default is +ANY +. If no type is specified, the default is +ANY +. If no name is specified, the default is " +* +".

+

+ + +The legal values for +ordering + are:

+

+ + + 

+ + + + + + + + + + + + + +
+

+ + + +fixed +

+		 +

+ + +Records are returned in the order they are defined in the zone file.

+
+

+ + + +random +

+		 +

+ + +Records are returned in some random order.

+
+

+ + + +cyclic +

+		 +

+ + +Records are returned in a round-robin order.

+
+

+ + +For example:

+

+    rrset-order {
+        class IN type A name "host.example.com" order random;
+        order cyclic;
+    };
+
+

+ + +will cause any responses for type A records in class IN that have " +host.example.com +" as a suffix, to always be returned in random order. All other records are returned in cyclic order.

+

+ + +If multiple +rrset-order + statements appear, they are not combined--the last one applies.

+

+ + +If no +rrset-order + statement is specified, then a default one of:

+
+
+
+    rrset-order { class ANY type ANY name "*"; order cyclic ;
+    };
+
+
+

+ + +is used.

+

+ + + +The + +rrset-order + + statement is not yet implemented in BIND 9. +

+
+
+ +
+ + +6.2.12.13 + +Tuning
+ +

+ + + 

+ + + + + + + + + + + + + + + + + + + + + +
+

+ + + +lame-ttl +

+		 +

+ + +Sets the number of seconds to cache a lame server indication. 0 disables caching. (This is NOT recommended.) Default is +600 + (10 minutes). Maximum value is +1800 + (30 minutes). +Not yet implemented in BIND 9. +

+
+

+ + + +max-ncache-ttl +

+		 +

+ + +To reduce network traffic and increase performance the server stores negative answers. +max-ncache-ttl + is used to set a maximum retention time for these answers in the server in seconds. The default
+ +max-ncache-ttl + is +10800 + seconds (3 hours).
+ +max-ncache-ttl + cannot exceed 7 days and will be silently truncated to 7 days if set to a greater value.

+
+

+ + + +max-cache-ttl +

+		 +

+ + + +max-cache-ttl + sets the maximum time for which the server will cache ordinary (positive) answers. The default is one week (7 days).

+
+

+ + + +min-roots +

+		 +

+ + +The minimum number of root servers that is required for a request for the root servers to be accepted. Default is +2 +. +Not yet implemented in BIND 9. +

+
+

+ + + +sig-validity-interval +

+		 +

+ + +Specifies the number of days into the future when DNSSEC signatures automatically generated as a result of dynamic updates (see + Dynamic Update + ) will expire. The default is +30 + days. The signature inception time is unconditionally set to one hour before the current time to allow for a limited amount of clock skew.

+
+
+
+ +
+ + +6.2.12.14 Deprecated Features
+ +

+ + + +use-ixfr + is deprecated in BIND 9. If you need to disable IXFR to a particular server or servers see the information on the +provide-ixfr + option in +server Statement Definition and Usage +. See also the description of IXFR in the section +Incremental Zone Transfers (IXFR) +.

+
+
+
+ +

+ + +6.2.13 +server + + + Statement Grammar

+ + + +

+server ip_addr {

+    [ bogus yes_or_no ; ]
+    [ provide-ixfr yes_or_no ; ]
+    [ request-ixfr yes_or_no ; ]
+    [ transfers number ; ]
+    [ transfer-format ( one-answer | many-answers ) ; ]
+        [ keys { string ; [ string ; [...]] } ; ]
+}; }
+
+ +
+
+ +

+ + +6.2.14 +server + + + Statement Definition and Usage

+ +

+ + +The +server + statement defines the characteristics to be associated with a remote nameserver.

+

+ + +If you discover that a remote server is giving out bad data, marking it as bogus will prevent further queries to it. The default value of +bogus + is +no +. +The + +bogus + + clause is not yet implemented in BIND 9. +

+

+ + +The +provide-ixfr + clause determines whether the local server, acting as master, will respond with an incremental zone transfer when the given remote server, a slave, requests it. If set to +yes +, incremental transfer will be provided whenever possible. If set to +no +, all transfers to the remote server will be nonincremental. If not set, the value of the +provide-ixfr +option in the global options block is used as a default.

+

+ + +The +request-ixfr + clause determines whether the local server, acting as a slave, will request incremental zone transfers from the given remote server, a master. If not set, the value of the +request-ixfr + option in the global options block is used as a default.

+

+ + +IXFR requests to servers that do not support IXFR will automatically fall back to AXFR. Therefore, there is no need to manually list which servers support IXFR and which ones do not; the global default of +yes + should always work. The purpose of the +provide-ixfr + and +request-ixfr + clauses is to make it possible to disable the use of IXFR even when both master and slave claim to support it, for example if one of the servers is buggy and crashes or corrupts data when IXFR is used.

+

+ + +The server supports two zone transfer methods. The first, +one-answer +, uses one DNS message per resource record transferred. +many-answers + packs as many resource records as possible into a message. +many-answers + is more efficient, but is only known to be understood by BIND 9, BIND 8.x, and patched versions of BIND 4.9.5. You can specify which method to use for a server with the +transfer-format +option. If +transfer-format +is not specified, the +transfer-format + specified by the +options + statement will be used.

+

+ + + +transfers + is used to limit the number of concurrent inbound zone transfers from the specified server. If no +transfers + clause is specified, the limit is set according to the +transfers-per-ns + option.

+

+ + +The +keys + clause is used to identify a +key_id +defined by the +key + statement, to be used for transaction security when talking to the remote server. The +key + statement must come before the +server + statement that references it. When a request is sent to the remote server, a request signature will be generated using the key specified here and appended to the message. A request originating from the remote server is not required to be signed by this key.

+

+ + +Although the grammar of the +keys + clause allows for multiple keys, only a single key per server is currently supported.

+
+
+ +

+ + +6.2.15 +trusted-keys + Statement Grammar

+ + +

+trusted-keys {
+    string number number number string ;
+    [ string number number number string ; [...]]
+}; }
+
+ + + +
+
+ +

+ + +6.2.16 +trusted-keys + Statement Definition and Usage

+ +

+ + +The +trusted-keys + statement defines DNSSEC security roots. See +DNSSEC for a description. A security root is defined when the public key for a non-authoritative zone is known, but cannot be securely obtained through DNS, either because it is the DNS root zone or its parent zone is unsigned. Once a key has been configured as a trusted key, it is treated as if it had been validated and proven secure. The resolver attempts DNSSEC validation on all DNS data in subdomains of a security root.

+

+ + +The +trusted-keys + statement can contain multiple key entries, each consisting of the key's domain name, flags, protocol, algorithm, and the base-64 representation of the key data.

+
+
+ +

+ + +6.2.17 +view + Statement Grammar

+ + +

+ view view name {
+      match_clients { address_match_list } ; 
+      [view_option; ...]
+      [zone_statement; ...]]
+};
+
+ +
+
+ +

+ + +6.2.18 +view + Statement Definition and Usage

+ +

+ + +The +view + statement is a powerful new feature of BIND 9 that lets a name server answer a DNS query differently depending on who is asking. It is particularly useful for implementing split DNS setups without having to run multiple servers.

+

+ + +Each +view + statement defines a view of the DNS namespace that will be seen by those clients whose IP addresses match the +address_match_list + of the view's +match-clients + clause. The order of the +view + statements is significant--a client query will be resolved in the context of the first +view + whose +match-clients +list matches the client's IP address.

+

+ + +Zones defined within a +view + statement will be only be accessible to clients that match the +view +. By defining a zone of the same name in multiple views, different zone data can be given to different clients, for example, "internal" and "external" clients in a split DNS setup.

+

+ + +Many of the options given in the +options + statement can also be used within a +view + statement, and then apply only when resolving queries with that view. When no a view-specific value is given, the value in the +options + statement is used as a default. Also, zone options can have default values specified in the +view + statement; these view-specific defaults take precedence over those in the +options + statement.

+

+ + +Views are class specific. If no class is given, class IN is assumed.

+

+ + +If there are no +view + statements in the config file, a default view that matches any client is automatically created in class IN, and any +zone + statements specified on the top level of the configuration file are considered to be part of this default view. If any explicit +view + statements are present, all +zone + statements must occur inside +view + statements.

+

+ + +A +zone + statement of type +hint + for the root zone (` +. +') does not strictly define a zone. Therefore, it should not be included in a +view + statement.

+

+ + +Here is an example of a typical split DNS setup implemented using +view + statements.

+ +
+
+view "internal" {
+               // This should match our internal networks.
+      match-clients { 10.0.0.0/8; };
+               // Provide recursive service to internal clients only.
+      recursion yes;
+               // Provide a complete view of the example.com zone
+               // including addresses of internal hosts.
+      zone "example.com" {
+            type master;
+            file "example-internal.db";
+      };
+  };
+
+  view "external" {
+      match-clients { any; };
+               // Refuse recursive service to external clients.
+      recursion no;
+               // Provide a restricted view of the example.com zone
+               // containing only publicly accessible hosts.
+      zone "example.com" {
+           type master;
+           file "example-external.db";
+      };
+  };
+
+
+
+ +

+ + +6.2.19 +zone + + + Statement Grammar

+ + +

+zone zone name [class] [{ 
+    type ( master|slave|hint|stub|forward ) ;
+    [ allow-query { address_match_list } ; ]
+    [ allow-transfer { address_match_list } ; ]
+    [ allow-update { address_match_list } ; ]
+    [ update-policy { update_policy_rule[...] } ; ]
+    [ allow-update-forwarding { address_match_list } ; ]
+    [ also-notify { [ ip_addr ; [ip_addr ; [...]]] } ; ]
+    [ check-names (warn|fail|ignore) ; ]
+    [ dialup true_or_false ; ]
+    [ file string ; ]
+    [ forward (only|first) ; ]
+    [ forwarders { [ ip_addr ; [ ip_addr ; [...]]] } ; ]
+    [ ixfr-base string ; ]
+    [ ixfr-tmp-file string ; ]
+    [ maintain-ixfr-base true_or_false ; ]
+    [ masters [port number] { ip_addr ; [ip_addr ; [...]] } ; ]
+    [ max-ixfr-log-size number ; ]
+    [ max-transfer-idle-in number ; ]
+    [ max-transfer-idle-out number ; ]
+    [ max-transfer-time-in number ; ]
+    [ max-transfer-time-out number ; ]
+    [ notify true_or_false ; ]
+    [ pubkey number number number string ; ]
+    [ transfer-source (ip4_addr | *) ; ]
+    [ transfer-source-v6 (ip6_addr | *) ; ]
+    [ sig-validity-interval number ; ]}]
+;
+
+
+ +

+ + +6.2.20 +zone + Statement Definition and Usage

+ +
+ +
+ + +6.2.20.1 Zone Types
+ + + + + + + + + + + + + + + + + + + + + +
+

+ + + +master +

+		 +

+ + +The server has a master copy of the data for the zone and will be able to provide authoritative answers for it.

+
+

+ + + +slave +

+		 +

+ + +A slave zone is a replica of a master zone. The masters list specifies one or more IP addresses that the slave contacts to update its copy of the zone. If a port is specified, the slave then checks to see if the zone is current and zone transfers will be done to the port given. If a file is specified, then the replica will be written to this file whenever the zone is changed, and reloaded from this file on a server restart. Use of a file is recommended, since it often speeds server start-up and eliminates a needless waste of bandwidth. Note that for large numbers (in the tens or hundreds of thousands) of zones per server, it is best to use a two level naming scheme for zone file names. For example, a slave server for the zone +example.com + might place the zone contents into a file called
+ +ex/example.com + where +ex/ +is just the first two letters of the zone name. (Most operating systems behave very slowly if you put 100K files into a single directory.)

+
+

+ + + +stub +

+		 +

+ + +A stub zone is similar to a slave zone, except that it replicates only the NS records of a master zone instead of the entire zone. Stub zones are not a standard part of the DNS; they are a peculiarity of BIND 4 and BIND 8 that relies heavily on the particular way the zone data is structured in those servers. BIND 9 attempts to emulate the BIND 4/8 stub zone feature for backwards compatibility, but we do not recommend its use in new configurations.

+

+ + +In BIND 4/8, zone transfers of a parent zone included the NS records from stub children of that zone. This meant that, in some cases, users could get away with configuring child stubs only in the master server for the parent zone. BIND 9 never mixes together zone data from different zones in this way. Therefore, if a BIND 9 master serving a parent zone has child stub zones configured, all the slave servers for the parent zone also need to have the same child stub zones configured..

+
+

+ + + +forward +

+		 +

+ + +A "forward zone" is a way to configure forwarding on a per-domain basis. A +zone + statement of type +forward + can contain a +forward + and/or +forwarders + statement, which will apply to queries within the domain given by the zone name. If no +forwarders + statement is present or an empty list for +forwarders + is given, then no forwarding will be done for the domain, cancelling the effects of any forwarders in the +options + statement. Thus if you want to use this type of zone to change the behavior of the global +forward + option (that is, "forward first to", then "forward only", or vice versa, but want to use the same servers as set globally) you need to respecify the global forwarders. +Domain-specific forwarding is not yet implemented in BIND 9. +

+
+

+ + + +hint +

+		 +

+ + +The initial set of root nameservers is specified using a "hint zone". When the server starts up, it uses the root hints to find a root nameserver and get the most recent list of root nameservers. If no hint zone is specified for class IN, the server users a compiled-in default set of root servers hints. Classes other than IN have no built-in defaults hints.

+
+ +
+
+ +
+ + +6.2.20.2 Class
+ +

+ + +The zone's name may optionally be followed by a class. If a class is not specified, class +IN + (for +Internet +), is assumed. This is correct for the vast majority of cases.

+

+ + +The +hesiod + + +class is named for an information service from MIT's Project Athena. It is used to share information about various systems databases, such as users, groups, printers and so on. The keyword +HS + is a synonym for hesiod.

+

+ + +Another MIT development is CHAOSnet, a LAN protocol created in the mid-1970s. Zone data for it can be specified with the +CHAOS + class.

+
+
+ +
+ + +6.2.20.3 Zone Options
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + + +allow-query +

+		 +

+ + +See the description of +allow-query + under +Access Control +.

+
+

+ + + +allow-transfer +

+		 +

+ + +See the description of +allow-transfer + under +Access Control +.

+
+

+ + + +allow-update +

+		 +

+ + +Specifies which hosts are allowed to submit Dynamic DNS updates for master zones. The default is to deny updates from all hosts.

+
+

+ + + +update-policy +

+		 +

+ + +Specifies a "Simple Secure Update" policy. See description in +Dynamic Update Policies +.

+
+

+ + + +allow-update-forwarding +

+		 +

+ + +Specifies which hosts are allowed to submit Dynamic DNS updates to slave zones to be forwarded to the master. The default is to deny update forwarding from all hosts. +Update forwarding is not yet implemented. +

+
+

+ + + +also-notify +

+		 +

+ + +Only meaningful if +notify + is active for this zone. The set of machines that will receive a +DNS NOTIFY + message for this zone is made up of all the listed nameservers (other than the primary master) for the zone plus any IP addresses specified with +also-notify +.
+ +also-notify + is not meaningful for stub zones. The default is the empty list +. +

+
+

+ + + +check-names +

+		 +

+ + +See +Name Checking +.
+ +Not yet implemented in BIND 9. +

+
+

+ + + +dialup +

+		 +

+ + +See the description of +dialup + under +Boolean Options +.
+ +Not yet implemented in BIND 9. +

+
+

+ + + +forward +

+		 +

+ + +Only meaningful if the zone has a forwarders list. The +only + value causes the lookup to fail after trying the forwarders and getting no answer, while +first + would allow a normal lookup to be tried.
+ +Not yet implemented in BIND 9. +

+
+

+ + + +forwarders +

+		 +

+ + +Used to override the list of global forwarders. If it is not specified in a zone of type +forward +, no forwarding is done for the zone; the global options are not used.

+

+ + + +Not yet implemented in BIND 9. +

+
+

+ + + +ixfr-base +

+		 +

+ + +Was used in BIND 8 to specify the name of the transaction log (journal) file for dynamic update and IXFR. BIND 9 ignores the option and constructs the name of the journal file by appending ". +jnl +" to the name of the zone file.

+
+

+ + + +max-transfer-time-in +

+		 +

+ + +See the description of
+ +max-transfer-time-in + under +Zone Transfers +.

+
+

+ + + +max-transfer-idle-in +

+		 +

+ + +See the description of
+ +max-transfer-idle-in + under +Zone Transfers +.

+
+

+ + + +max-transfer-time-out +

+		 +

+ + +See the description of
+ +max-transfer-time-out + under +Zone Transfers +.

+
+

+ + + +max-transfer-idle-out +

+		 +

+ + +See the description of
+ +max-transfer-idle-out + under +Zone Transfers +.

+
+

+ + + +notify +

+		 +

+ + +See the description of +notify + under +Boolean Options +.

+
+

+ + + +pubkey +

+		 +

+ + +In BIND 8, this option was intended for specifying a public zone key for verification of signatures in DNSSEC signed zones when they are loaded from disk. BIND 9 does not verify signatures on loading and ignores the option.

+
+

+ + + +sig-validity-interval +

+		 +

+ + +See the description of +sig-validity-interval + in +Tuning +.

+
+

+ + + +transfer-source +

+		 +

+ + +Determines which local address will be bound to the IPv4 TCP connection used to fetch this zone. If not set, it defaults to a system controlled value which will usually be the address of the interface "closest to" the remote end. This address must appear in the remote end's +allow-transfer + option for this zone if one is specified.

+
+

+ + +transfer-source-v6

+		 +

+ + +Similar to transfer-source, but for zone transfers performed using IPv6.

+
+ +
+
+ +
+ + +6.2.20.4 + +Dynamic Update Policies
+ +

+ + +BIND 9 supports two alternative methods of granting clients the right to perform dynamic updates to a zone, configured by the +allow-update + and +update-policy + option, respectively.

+

+ + +The +allow-update + clause works the same way as in previous versions of BIND. It grants given clients the permission to update any record of any name in the zone.

+

+ + +The +update-policy + clause is new in BIND 9 and allows more fine-grained control over what updates are allowed. A set of rules is specified, where each rule either grants or denies permissions for one or more names to be updated by one or more identities. If the dynamic update request message is signed (that is, it includes either a TSIG or SIG(0) record), the identity of the signer can be determined.

+

+ + +Rules are specified in the +update-policy + zone option, and are only meaningful for master zones. When the +update-policy + statement is present, it is a configuration error for the +allow-update + statement to be present. The +update-policy + statement only examines the signer of a message; the source address is not relevant.

+

+ + +This is how a rule definition looks:

+ +
+( grant | deny ) identity nametype name [ types ]
+
+ +

+ + +Each rule grants or denies privileges. Once a messages has successfully matched a rule, the operation is immediately granted or denied and no further rules are examined. A rule is matched when the signer matches the identity field, the name matches the name field, and the type is specified in the type field.

+

+ + +The identity field specifies a name or a wildcard name. The nametype field has 4 values: +name +, +subdomain +, +wildcard +, and +self + + +.

+ + + + + + + + + + + + + + + + + +
+
+ + + +name +
+		 +

+ + +Matches when the updated name is the same as the name in the name field.

+
+
+ + + +subdomain +
+		 +

+ + +Matches when the updated name is a subdomain of the name in the name field.

+
+
+ + + +wildcard +
+		 +

+ + +Matches when the updated name is a valid expansion of the wildcard name in the name field.

+
+
+ + + +self +
+		 +

+ + +Matches when the updated name is the same as the message signer. The name field is ignored.

+
+

+ + +If no types are specified, the rule matches all types except SIG, NS, SOA, and NXT. Types may be specified by name, including "ANY" (ANY matches all types except NXT, which can never be updated).

+

- + -6.3 Dynamic Updates

+6.3 Zone File -

- +

+ +

+ -Access to the dynamic update facility should be strictly limited. In earlier versions of BIND the only way to do this was based on the IP address of the host requesting the update. BINDv9 also supports authenticating updates cryptographically by means of transaction signatures (TSIG). The use of TSIG is strongly recommended.

-

- - -Some sites choose to keep all dynamically updated DNS data in a subdomain and delegate that subdomain to a separate zone. This way, the top-level zone containing critical data such as the IP addresses of public web and mail servers need not allow dynamic update at all.

+6.3.1 + +Types of Resource Records and When to Use Them

+ +

+ + +This section, largely borrowed from RFC 1034, describes the concept of a Resource Record (RR) and explains when each is used. Since the publication of RFC 1034, several new RRs have been identified and implemented in the DNS. These are also included.

+
+ +
+ + +6.3.1.1 Resource Records
+ +

+ + +A domain name identifies a node. Each node has a set of resource information, which may be empty. The set of resource information associated with a particular name is composed of separate RRs. The order of RRs in a set is not significant and need not be preserved by nameservers, resolvers, or other parts of the DNS. However, sorting of multiple RRs is permitted for optimization purposes, for example, to specify that a particular nearby server be tried first. See +The sortlist Statement + and +RRset Ordering + for details.

+

+ + +The components of a Resource Record are

+ + + + + + + + + + + + + + + + + + + + + +
+

+ + +owner name

+		 +

+ + +the domain name where the RR is found.

+
+

+ + +type

+		 +

+ + +an encoded 16 bit value that specifies the type of the resource in this resource record. Types refer to abstract resources.

+
+

+ + +TTL

+		 +

+ + +the time to live of the RR. This field is a 32 bit integer in units of seconds, and is primarily used by resolvers when they cache RRs. The TTL describes how long a RR can be cached before it should be discarded.

+
+

+ + +class

+		 +

+ + +an encoded 16 bit value that identifies a protocol family or instance of a protocol.

+
+

+ + +RDATA

+		 +

+ + +the type and sometimes class-dependent data that describes the resource.

+
+

+ + +The following are +types + of valid RRs (some of these listed, although not obsolete, are experimental (x) or historical (h) and no longer in general use):

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + +A

+		 +

+ + +a host address.

+
+

+ + +A6

+		 +

+ + +an IPv6 address.

+
+

+ + +AAAA

+		 +

+ + +Obsolete format of IPv6 address

+
+

+ + +AFSDB

+		 +

+ + +(x) location of AFS database servers. Experimental.

+
+

+ + +CNAME

+		 +

+ + +identifies the canonical name of an alias.

+
+

+ + +DNAME

+		 +

+ + +for delegation of reverse addresses. Replaces the domain name specified with another name to be looked up. Described in RFC 2672.

+
+

+ + +HINFO

+		 +

+ + +identifies the CPU and OS used by a host.

+
+

+ + +ISDN

+		 +

+ + +(x) representation of ISDN addresses. Experimental.

+
+

+ + +KEY

+		 +

+ + +stores a public key associated with a DNS name.

+
+

+ + +LOC

+		 +

+ + +(x) for storing GPS info. See RFC 1876. Experimental.

+
+

+ + +MX

+		 +

+ + +identifies a mail exchange for the domain. See RFC 974 for details.

+
+

+ + +NS

+		 +

+ + +the authoritative nameserver for the domain.

+
+

+ + +NXT

+		 +

+ + +used in DNSSEC to securely indicate that RRs with an owner name in a certain name interval do not exist in a zone and indicate what RR types are present for an existing name. See RFC 2535 for details.

+
+

+ + +PTR

+		 +

+ + +a pointer to another part of the domain name space.

+
+

+ + +RP

+		 +

+ + +(x) information on persons responsible for the domain. Experimental.

+
+

+ + +RT

+		 +

+ + +(x) route-through binding for hosts that do not have their own direct wide area network addresses. Experimental.

+
+

+ + +SIG

+		 +

+ + +("signature") contains data authenticated in the secure DNS. See RFC 2535 for details.

+
+

+ + +SOA

+		 +

+ + +identifies the start of a zone of authority.

+
+

+ + +SRV

+		 +

+ + +information about well known network services (replaces WKS).

+
+

+ + +WKS

+		 +

+ + +(h) information about which well known network services, such as SMTP, that a domain supports. Historical, replaced by newer RR SRV.

+
+

+ + +X25

+		 +

+ + +(x) representation of X.25 network addresses. Experimental.

+
+

+ + +The following +classes + of resource records are currently valid in the DNS:

+ + + + + + + + +
+

+ + +IN

+		 +

+ + +the Internet system.

+
+

+ + +For information about other, older classes of RRs, see +Classes of Resource Records + in the Appendix.

+
+

+ + + +RDATA + is the type-dependent or class-dependent data that describes the resource:

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + +A

+		 +

+ + +for the IN class, a 32 bit IP address.

+
+

+ + +A6

+		 +

+ + +maps a domain name to an IPv6 address, with a provision for indirection for leading "prefix" bits.

+
+

+ + +CNAME

+		 +

+ + +a domain name.

+
+

+ + +DNAME

+		 +

+ + +provides alternate naming to an entire subtree of the domain name space, rather than to a single node. It causes some suffix of a queried name to be substituted with a name from the DNAME record's RDATA.

+
+

+ + +MX

+		 +

+ + +a 16 bit preference value (lower is better) followed by a host name willing to act as a mail exchange for the owner domain.

+
+

+ + +NS

+		 +

+ + +a fully qualified domain name.

+
+

+ + +PTR

+		 +

+ + +a fully qualified domain name.

+
+

+ + +SOA

+		 +

+ + +several fields.

+
+

+ + +The owner name is often implicit, rather than forming an integral part of the RR. For example, many nameservers internally form tree or hash structures for the name space, and chain RRs off nodes. The remaining RR parts are the fixed header (type, class, TTL) which is consistent for all RRs, and a variable part (RDATA) that fits the needs of the resource being described.

+

+ + +The meaning of the TTL field is a time limit on how long an RR can be kept in a cache. This limit does not apply to authoritative data in zones; it is also timed out, but by the refreshing policies for the zone. The TTL is assigned by the administrator for the zone where the data originates. While short TTLs can be used to minimize caching, and a zero TTL prohibits caching, the realities of Internet performance suggest that these times should be on the order of days for the typical host. If a change can be anticipated, the TTL can be reduced prior to the change to minimize inconsistency during the change, and then increased back to its former value following the change.

+

+ + +The data in the RDATA section of RRs is carried as a combination of binary strings and domain names. The domain names are frequently used as "pointers" to other data in the DNS.

-

Return to BINDv9 Administrator Reference Manual + +

+ + +6.3.1.2 Textual expression of RRs
+ +

+ + +RRs are represented in binary form in the packets of the DNS protocol, and are usually represented in highly encoded form when stored in a nameserver or resolver. In the examples provided in RFC 1034, a style similar to that used in master files was employed in order to show the contents of RRs. In this format, most RRs are shown on a single line, although continuation lines are possible using parentheses.

+

+ + +The start of the line gives the owner of the RR. If a line begins with a blank, then the owner is assumed to be the same as that of the previous RR. Blank lines are often included for readability.

+

+ + +Following the owner, we list the TTL, type, and class of the RR. Class and type use the mnemonics defined above, and TTL is an integer before the type field. In order to avoid ambiguity in parsing, type and class mnemonics are disjoint, TTLs are integers, and the type mnemonic is always last. The IN class and TTL values are often omitted from examples in the interests of clarity.

+

+ + +The resource data or RDATA section of the RR are given using knowledge of the typical representation for the data.

+

+ + +For example, we might show the RRs carried in a message as:

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + + +ISI.EDU. +

+		 +

+ + + +MX +

+		 +

+ + + +10 VENERA.ISI.EDU. +

+
+

+ + + + + 

+		 +

+ + + +MX +

+		 +

+ + + +10 VAXA.ISI.EDU +

+
+

+ + + +VENERA.ISI.EDU +

+		 +

+ + + +A +

+		 +

+ + + +128.9.0.32 +

+
+

+ + + + + 

+		 +

+ + + +A +

+		 +

+ + + +10.1.0.52 +

+
+

+ + + +VAXA.ISI.EDU +

+		 +

+ + + +A +

+		 +

+ + + +10.2.0.27 +

+
+

+ + + + + 

+		 +

+ + + +A +

+		 +

+ + + +128.9.0.33 +

+
+

+ + +The MX RRs have an RDATA section which consists of a 16 bit number followed by a domain name. The address RRs use a standard IP address format to contain a 32 bit internet address.

+

+ + +This example shows six RRs, with two RRs at each of three domain names.

+

+ + +Similarly we might see:

+ + + + + + + + + + + +
+

+ + + +XX.LCS.MIT.EDU. IN +

+		 +

+ + + +A +

+		 +

+ + + +10.0.0.44 +

+
+

+ + + +CH +

+		 +

+ + + +A +

+		 +

+ + + +MIT.EDU. 2420 +

+
+

+ + +This example shows two addresses for +XX.LCS.MIT.EDU +, each of a different class.

+
+
+ +

+ + +6.3.2 Discussion of MX Records

+ +

+ + +As described above, domain servers store information as a series of resource records, each of which contains a particular piece of information about a given domain name (which is usually, but not always, a host). The simplest way to think of a RR is as a typed pair of datum, a domain name matched with relevant data, and stored with some additional type information to help systems determine when the RR is relevant.

+

+ + +MX records are used to control delivery of email. The data specified in the record is a priority and a domain name. The priority controls the order in which email delivery is attempted, with the lowest number first. If two priorities are the same, a server is chosen randomly. If no servers at a given priority are responding, the mail transport agent will fall back to the next largest priority. Priority numbers do not have any absolute meaning - they are relevant only respective to other MX records for that domain name. The domain name given is the machine to which the mail will be delivered. It +must + have an associated A record--a CNAME is not sufficient.

+

+ + +For a given domain, if there is both a CNAME record and an MX record, the MX record is in error, and will be ignored. Instead, the mail will be delivered to the server specified in the MX record pointed to by the CNAME.

+

+ + +For example:

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + + +example.com. +

+		 +

+ + + +IN +

+		 +

+ + + +MX +

+		 +

+ + + +10 +

+		 +

+ + + +mail.example.com. +

+
+

+ + + + + 

+		 +

+ + + +IN +

+		 +

+ + + +MX +

+		 +

+ + + +10 +

+		 +

+ + + +mail2.example.com. +

+
+

+ + + + + 

+		 +

+ + + +IN +

+		 +

+ + + +MX +

+		 +

+ + + +20 +

+		 +

+ + + +mail.backup.org. +

+
+

+ + + +mail.example.com. +

+		 +

+ + + +IN +

+		 +

+ + + +A +

+		 +

+ + + +10.0.0.1 +

+		 +

+ + + + + 

+
+

+ + + +mail2.example.com. +

+		 +

+ + + +IN +

+		 +

+ + + +A +

+		 +

+ + + +10.0.0.2 +

+		 +

+ + + + + 

+
+

+ + +Mail delivery will be attempted to +mail.example.com + and +mail2.example.com + (in any order), and if neither of those succeed, delivery to +mail.backup.org + will be attempted.

+
+
+ +

+ + +6.3.3 + +Setting TTLs

+ +

+ + +The time to live of the RR field is a 32 bit integer represented in units of seconds, and is primarily used by resolvers when they cache RRs. The TTL describes how long a RR can be cached before it should be discarded. The following three types of TTL are currently used in a zone file.

+

+ + + 

+ + + + + + + + + + + + + +
+

+ + +SOA

+		 +

+ + +The last field in the SOA is the negative caching TTL. This controls how long other servers will cache no-such-domain (NXDOMAIN) responses from you.

+

+ + +The maximum time for negative caching is 3 hours (3h).

+
+

+ + +$TTL

+		 +

+ + +The $TTL directive at the top of the zone file (before the SOA) gives a default TTL for every RR without a specific TTL set.

+
+

+ + +RR TTLs

+		 +

+ + +Each RR can have a TTL as the second field in the RR, which will control how long other servers can cache the it.

+
+

+ + +All of these TTLs default to units of seconds, though units can be explicitly specified, for example, +1h30m +.

+
+
+ +

+ + +6.3.4 Inverse Mapping in IPv4

+ +

+ + +Reverse name resolution (that is, translation from IP address to name) is achieved by means of the +in-addr.arpa + domain and PTR records. Entries in the in-addr.arpa domain are made in least-to-most significant order, read left to right. This is the opposite order to the way IP addresses are usually written. Thus, a machine with an IP address of 10.1.2.3 would have a corresponding in-addr.arpa name of
+3.2.1.10.in-addr.arpa. This name should have a PTR resource record whose data field is the name of the machine or, optionally, multiple PTR records if the machine has more than one name. For example, in the +example.com + domain:

+

+
+ 
+ +
+$ORIGIN			2.1.10.in-addr.arpa
+3			IN PTR foo.example.com.
+
+

+ + +(Note: The +$ORIGIN + lines in the examples are for providing context to the examples only--they do not necessarily appear in the actual usage. They are only used here to indicate that the example is relative to the listed origin.)

+
+
+ +

+ + +6.3.5 Other Zone File Directives

+ +

+ + +The Master File Format was initially defined in RFC 1035 and has subsequently been extended. While the Master File Format itself is class independent all records in a Master File must be of the same class.

+

+ + +Master File Directives include +$ORIGIN +, +$INCLUDE +, and +$TTL. +

+
+ +
+ + +6.3.5.1 The +$ORIGIN + Directive
+ +

+ + +Syntax: +$ORIGIN < + +domain-name + +> + +[ + +< + +comment + +> + +] +

+

+ + + +$ORIGIN +sets the domain name that will be appended to any unqualified records. When a zone is first read in there is an implicit +$ORIGIN +< +zone-name +> +. + The current +$ORIGIN + is appended to the domain specified in the +$ORIGIN + argument if it is not absolute.

+ +
+$ORIGIN example.com
+WWW     CNAME   MAIN-SERVER
+
+ +is equivalent to + +
+WWW.EXAMPLE.COM CNAME MAIN-SERVER.EXAMPLE.COM.
+
+
+
+ +
+ + +6.3.5.2 The +$INCLUDE + Directive
+ +

+ + +Syntax: +$INCLUDE < + +filename + +> + +[ + +< + +origin + +> + +] [ + +< + +comment + +> + +] +

+

+ + +Read and process the file +filename + as if it were included into the file at this point. If +origin + is specified the file is processed with +$ORIGIN +set to that value, otherwise the current +$ORIGIN + is used.

+

+ + + +NOTE: +The behavior when +origin + is specified differs from that described in RFC 1035. The origin and current domain revert to the values they were prior to the +$INCLUDE + once the file has been read.

+
+
+ +
+ + +6.3.5.3 The +$TTL + Directive
+ +

+ + +Syntax: +$TTL < + +default-ttl + +> + +[ + +< + +comment + +> + +] +

+

+ + +Set the default Time To Live (TTL) for subsequent records with undefined TTLs. Valid TTLs are of the range 0-2147483647 seconds.

+

+ + + +$TTL + is defined in RFC 2308.

+
+
+
+ +

+ + +6.3.6 BIND Master File Extension: the +$GENERATE + Directive

+ +

+$GENERATE
+
+

+ + +Syntax: +$GENERATE < + +range + +> < + +lhs + +> < + +type + +> < + +rhs + +> + +[ + +< + +comment + +> + +] +

+

+ + + +$GENERATE + is used to create a series of resource records that only differ from each other by an iterator. +$GENERATE +can be used to easily generate the sets of records required to support sub /24 reverse delegations described in RFC 2317: Classless IN-ADDR.ARPA delegation.

+ +
+
+$ORIGIN 0.0.192.IN-ADDR.ARPA.
+$GENERATE 1-2 0 NS SERVER$.EXAMPLE.
+$GENERATE 1-127 $ CNAME $.0
+
+

+ + +is equivalent to

+
+
+0.0.0.192.IN-ADDR.ARPA NS SERVER1.EXAMPLE.
+0.0.0.192.IN-ADDR.ARPA NS SERVER2.EXAMPLE.
+1.0.0.192.IN-ADDR.ARPA CNAME 1.0.0.0.192.IN-ADDR.ARPA
+2.0.0.192.IN-ADDR.ARPA CNAME 2.0.0.0.192.IN-ADDR.ARPA
+...
+127.0.0.192.IN-ADDR.ARPA CNAME 127.0.0.0.192.IN-ADDR.ARPA
+.
+
+

+ + + + + 

+ + + + + + + + + + + + + + + + + +
+

+ + + +range +

+		 +

+ + +This can be one of two forms: start-stop or start-stop/step. If the first form is used then step is set to 1. All of start, stop and step must be positive.

+
+

+ + + +lhs +

+		 +

+ + + +lhs + describes the owner name of the resource records to be created. Any single +$ + symbols within the +lhs + side are replaced by the iterator value. To get a $ in the output use a double +$ +, e.g. +$$ +. If the +lhs + is not absolute, the current +$ORIGIN +is appended to the name.

+
+

+ + + +type +

+		 +

+ + +At present the only supported types are PTR, CNAME and NS.

+
+

+ + + +rhs +

+		 +

+ + +rhs is a domain name. It is processed similarly to lhs.

+
+

+ + +The +$GENERATE + directive is a BIND extension and not part of the standard zone file format. +It is not yet implemented in BIND 9. +

+
+
+ +

+ + +6.3.7 Signals

+ +

+ + +Certain UNIX signals cause the name server to take specific actions, as described in the following table. These signals can be sent using the +kill + command.

+

+ + + 

+ + + + + + + + + + + + + + + + + +
+

+ + + +SIGHUP +

+		 +

+ + +Causes the server to read +named.conf + and reload the database.

+
+

+ + + +SIGTERM +

+		 +

+ + +Causes the server to clean up and exit.

+
+

+ + + +SIGINT +

+		 +

+ + +Causes the server to clean up and exit.

+
+

+ + + +SIGQUIT +

+		 +

+ + +Causes the server to clean up and exit.

+
+
+
+
+

Return to BIND 9 Administrator Reference Manual table of contents.

+ diff --git a/doc/arm/Bv9ARM.7.html b/doc/arm/Bv9ARM.7.html index dea5d05e26..a630640dc0 100644 --- a/doc/arm/Bv9ARM.7.html +++ b/doc/arm/Bv9ARM.7.html @@ -1,298 +1,208 @@ - - - - - Section 7. Troubleshooting + Section 7. BIND 9 Security Considerations

    -Section 7. Troubleshooting

    +Section 7. BIND 9 Security Considerations

    - - -7.1 Common Log Messages and What They Mean

    -
-
-
    -
    -lame server
    -
-

-ns named[111]: Lame server on 'www.example.com' (in 'example.com'?): [192.168.0.2].53 'ns2.example.com'
-
+7.1 + +Access Control Lists + +

+ + +Access Control Lists (ACLs), are address match lists that you can set up and nickname for future use in +allow-query +, +allow-recursion +, +blackhole +, +allow-transfer +, etc.

-This is a harmless error message. It means that the server at 192.168.0.2 ( -ns2.example.com -) is listed as a nameserver for " -example.com -", but it doesn't really know anything about -example.com -.

+Using ACLs allows you to have finer control over who can access your nameserver, without cluttering up your config files with huge lists of IP addresses.

-If this is a zone under your control, check each of the nameservers to ensure that they are configured to answer questions properly.

+It is a +good idea + to use ACLs, and to control access to your server. Limiting access to your server by outside parties can help prevent spoofing and DoS attacks against your server.

-If it's a zone out on the Internet, it would be nice to notify the owners of the domain in question so that they can take a look at it. In practice, though, not many people have time to do this.

-
-
-
    -
    - - -bad referral
    -
-

-ns named[111]: bad referral (other.com !< subdomain.other.com)
-
-

- - -This indicates that your nameserver ( -ns.example.com -) queried the nameserver for -example2.com - to find out how to get to -subdomain.example2.com -. The name server -example2.com - told your nameserver that -subdomain.example2.com - was delegated to some -other.example2.com -, so your nameserver queried that.

-

- - - -someother.example2.com - didn't think that -subdomain.example2.com - had been delegated to it, so it referred your server ( -ns.example.com -) back to the -example2.com - nameserver.

-
-
-
    -
    - - -not authoritative for
    -
-

-ns named-xfer[111]: [192.168.0.1] not authoritative for example.com, SOA query got rcode 0, aa 0, ancount 1, aucount 0
+Here is an example of how to properly apply ACLs:

+
+
+ 
+// Set up an ACL named "bogusnets" that will block RFC1918 space,
+// which is commonly used in spoofing attacks.
+ 
+acl bogusnets { 0.0.0.0/8; 1.0.0.0/8; 2.0.0.0/8; 192.0.2.0/24; 224.0.0.0/3;
+10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16; };
+
+// Set up an ACL called our-nets. Replace this with the real IP numbers.
+ 
+acl our-nets { x.x.x.x/24; x.x.x.x/21; };
+ 
+options {
+  ...
+  ...
+  allow-query { our-nets; };
+  allow-recursion { our-nets; };
+  ...
+  blackhole { bogusnets; };
+  ...
+};
+zone "example.com" {
+  type master;
+  file "m/example.com";
+  allow-query { any; };
+};
+
 

 

 
  
-This error usually shows up on a slave server. It indicates that the master server is not answering authoritatively for the zone. This usually happens when the zone is rejected (while 
-named
- is loading) on the master server. Check the logs on the master server. If ancount -- 0, you may be pointing at the wrong master server for the zone.

+This allows recursive queries of the server from the outside unless recursion has been previously disabled.

+

+
+ 
+For more information on how to use ACLs to protect your server, see the 
+AUSCERT
+ advisory at

+
+ftp://ftp.auscert.org.au/pub/auscert/advisory/AL-1999.004.dns_dos
- -

-ns named[111]: master zone "example.com" (IN) rejected due to errors (serial111)
-
+7.2 +chroot + and +setuid + (for UNIX servers) +

-This indicates that the -example.com - zone was rejected because of an error in the zone file. Check the lines above this error. -named - will usually tell you what it didn't like and where to find it in the zone file.

-
-
-
    -
    +On UNIX servers, it is possible to run BIND in a +chrooted + environment ( +chroot() +) by specifying the " +-t +" option. This can help improve system security by placing BIND in a "sandbox," which will limit the damage done if a server is compromised.

    +

    -no NS RRs found

    -
-

-ns named[111]: Zone "example.com" (file example.com.db): no NS RRs found at zonetop
-
+Another useful feature in the UNIX version of BIND is the ability to run the daemon as a nonprivileged user ( +-u + +user + ). We suggest running as a nonprivileged user when using the +chroot + feature.

- - -The -example.com.db - file is missing NS records at the top of the zone (in the SOA section). Check to make sure they exist and that there is white space (spaces or tabs) in front of them. White spaces matter here.

-
-
-
    -
    - - -no default TTL set
    -
-

-ns named[111]: Zone "example.com" (file example.com.db): No default TTL set using SOA minimum instead
-
-

- - -You will need to add a -$TTL - to the top of the -example.com.db - zone file. See RFC 2308, or -Setting TTLs - for information on how to use -$TTL -.

-
-
-
    -
    - - -no root nameserver for class
    -
-

-findns: No root nameservers for class IN?
-
-

- - -Your nameserver is having problems finding the root nameservers. Check your root hints file to make sure it is not corrupted. Also, make sure that your nameserver can reach the Internet.

-

- - -If you are running an internal root nameserver, make sure it is configured properly and is answering queries.

-
-
-
    -
    - - -address already in use
    -
-

-ctl_server: bind: Address already in use
-
-

- - -This usually indicates that another copy of BIND is already running. Verify that you have killed old copies of the daemon.

-

- - -This can also pop up if you originally ran named as "root" and now run it as a regular user. named may have left behind an ndc control socket that is owned by root if it crashed, or was not killed gracefully.

-

- - -This means that the regular user wouldn't be able to delete it, so it would think named is still running. The solution is to remove any ndc sockets in -/usr/local/etc -, or -/var/run -, etc.

-
-
-
-
    -

    - - -7.2 Common Problems

    -
+ + +Here is an example command line to load BIND in a +chroot() + sandbox,
+ +/var/named +, and to run +named setuid + to user 202:

+ +
+/usr/local/bin/named -u 202 -t /var/named
+

    - - -7.2.1 It's not working; how can I figure out what's wrong?

    + + +7.2.1 The +chroot + Environment

- + -The best solution to solving installation and configuration issues is to take preventative measures by setting up logging files beforehand (see the sample configurations in -Sample Configuration and Logging. -). The log files provide a source of hints and information that can be used to figure out what went wrong and how to fix the problem.

+In order for a +chroot() + environment to work properly in a particular directory (for example, +/var/named +), you will need to set up an environment that includes everything BIND needs to run. From BIND's point of view, +/var/named + is the root of the filesystem. You will need +/dev/null +, and any library directories and files that BIND needs to run on your system. Please consult your operating system's instructions if you need help figuring out which library files you need to copy over to the +chroot() + sandbox.

+

+ + +If you are running an operating system that supports static binaries, you can also compile BIND statically and avoid the need to copy system libraries over to your +chroot() + sandbox.

+
+
+
    +

    + + +7.2.2 Using the +setuid + Function

    +
+

+ + +Prior to running the +named + daemon, use the +touch + utility (to change file access and modification times) or the +chown + utility (to set the user id and/or group id) on files to which you want BIND to write.

    - + -7.3 Incrementing and Changing the Serial Number

    +7.3 Dynamic Updates

- + -Zone serial numbers are just numbers--they aren't date related. A lot of people set them to a number that represents a date, usually of the form YYYYMMDDRR. A number of people have been testing these numbers for Y2K compliance and have set the number to the year 2000 to see if it will work. They then try to restore the old serial number. This will cause problems, because serial numbers are used to indicate that a zone has been updated. If the serial number on the secondary server is lower than the serial number on the primary, the secondary server will attempt to update its copy of the zone.

+Access to the dynamic update facility should be strictly limited. In earlier versions of BIND the only way to do this was based on the IP address of the host requesting the update. BIND 9BIND 9 also supports authenticating updates cryptographically by means of transaction signatures (TSIG). The use of TSIG is strongly recommended.

- + -Setting the serial number to a lower number on the primary server than the secondary server means that the secondary will not perform updates to its copy of the zone.

-

- - -The solution to this is to add 2147483647 (2^31-1) to the number, reload the zone and make sure all secondaries have updated to the new zone serial number, then reset the number to what you want it to be, and reload the zone again.

-
-
-
    -

    - - -7.4 Where Can I Get Help?

    -
-

- - -The Internet Software Consortium (ISC) offers a wide range of support and service agreements for BIND and DHCP servers. Four levels of premium support are available and each level includes support for all ISC programs, significant discounts on products and training, and a recognized priority on bug fixes and non-funded feature requests. In addition, ISC offers a standard support agreement package which includes services ranging from bug fix announcements to remote support. It also includes training in BIND and DHCP.

-

- - -To discuss arrangements for support, contact -info@isc.org -or visit the ISC web page at
- -http://www.isc.org/services/support/ - to read more.

-
-
-

Return to BINDv9 Administrator Reference Manual +Some sites choose to keep all dynamically updated DNS data in a subdomain and delegate that subdomain to a separate zone. This way, the top-level zone containing critical data such as the IP addresses of public web and mail servers need not allow dynamic update at all.

+
+

Return to BIND 9 Administrator Reference Manual table of contents.

+ diff --git a/doc/arm/Bv9ARM.8.html b/doc/arm/Bv9ARM.8.html index 11c17ec692..3cbc9faff6 100644 --- a/doc/arm/Bv9ARM.8.html +++ b/doc/arm/Bv9ARM.8.html @@ -1,470 +1,83 @@ - - - - - Appendices + Section 8. Troubleshooting -
- +
    +

    + -Appendices

    +Section 8. Troubleshooting
+
-
- +
    +

    + -Appendix A. Acknowledgements

    -
-

- - -A.1 A Brief History of the DNS and BIND

-

- - -Although the "official" beginning of the Domain Name System occurred in 1984 with the publication of RFC 920, the core of the new system was described in 1983 in RFCs 882 and 883. From 1984 to 1987, the ARPAnet (the precursor to today's Internet) became a testbed of experimentation for developing the new naming/addressing scheme in an rapidly expanding, operational network environment. New RFCs were written and published in 1987 that modified the original documents to incorporate improvements based on the working model. RFC 1034, "Domain Names-Concepts and Facilities," and RFC 1035, "Domain Names-Implementation and Specification" were published and became the standards upon which all DNS implementations are built.

-

- - -The first working domain name server, called "Jeeves," was written in 1983-84 by Paul Mockapetris for operation on DEC Tops-20 machines located at the University of Southern California's Information Sciences Institute (USC-ISI) and SRI International's Network Information Center (SRI-NIC). A DNS server for Unix machines, the Berkeley Internet Name Domain (BIND) package, was written soon after by a group of graduate students at the University of California at Berkeley under a grant from the US Defense Advanced Research Projects Administration (DARPA). Versions of BIND through 4.8.3 were maintained by the Computer Systems Research Group (CSRG) at UC Berkeley. Douglas Terry, Mark Painter, David Riggle and Songnian Zhou made up the initial BIND project team. After that, additional work on the software package was done by Ralph Campbell. Kevin Dunlap, a Digital Equipment Corporation employee on loan to the CSRG, worked on BIND for 2 years, from 1985 to 1987. Many other people also contributed to BIND development during that time: Doug Kingston, Craig Partridge, Smoot Carl-Mitchell, Mike Muuss, Jim Bloom and Mike Schwartz. BIND maintenance was subsequently handled by Mike Karels and O. Kure.

-

- - -BIND versions 4.9 and 4.9.1 were released by Digital Equipment Corporation (now Compaq Computer Corporation). Paul Vixie, then a DEC employee, became BIND's primary caretaker. Paul was assisted by Phil Almquist, Robert Elz, Alan Barrett, Paul Albitz, Bryan Beecher, Andrew Partan, Andy Cherenson, Tom Limoncelli, Berthold Paffrath, Fuat Baran, Anant Kumar, Art Harkin, Win Treese, Don Lewis, Christophe Wolfhugel, and others.

-

- - -BIND Version 4.9.2 was sponsored by Vixie Enterprises. Paul Vixie became BIND's principal architect/programmer.

-

- - -BIND versions from 4.9.3 onward have been developed and maintained by the Internet Software Consortium with support being provided by ISC's sponsors. As co-architects/programmers, Bob Halley and Paul Vixie released the first production-ready version of BIND version 8 in May 1997.

-

- - -BIND development work is made possible today by the sponsorship of several corporations, and by the tireless work efforts of numerous individuals.

- -

- - -Appendix B. - -Historical DNS Information

+8.1 Common Problems +
-

- +
    +

    + -B.1 - -Classes of Resource Records

    -
    -

    - - -B.1.1 HS = hesiod

    +8.1.1 It's not working; how can I figure out what's wrong?

+

- + -The -hesiod -class is an information service developed by MIT's Project Athena. It is used to share information about various systems databases, such as users, groups, printers and so on. The keyword -hs - is a synonym for hesiod.

+The best solution to solving installation and configuration issues is to take preventative measures by setting up logging files beforehand. (See the sample configurations) in Section 3. The log files provide a source of hints and information that can be used to figure out what went wrong and how to fix the problem.

+
-

- +
    +

    + -B.1.2 CH = chaos

    -

    - - -The -chaos - class is used to specify zone data for the MIT-developed CHAOSnet, a LAN protocol created in the mid-1970s.

    -

-
- -

- - -Appendix C. - -Bibliography (and Suggested Reading)

-
-

- - -C.1 - -Request for Comments (RFCs)

+8.2 Incrementing and Changing the Serial Number +

- + -Specification documents for the Internet protocol suite, including the DNS, are published as part of the Request for Comments (RFCs) series of technical notes. The standards themselves are defined by the Internet Engineering Task Force (IETF) and the Internet Engineering Steering Group (IESG). RFCs can be obtained online via FTP at
+Zone serial numbers are just numbers--they aren't date related. A lot of people set them to a number that represents a date, usually of the form YYYYMMDDRR. A number of people have been testing these numbers for Y2K compliance and have set the number to the year 2000 to see if it will work. They then try to restore the old serial number. This will cause problems because serial numbers are used to indicate that a zone has been updated. If the serial number on the slave server is lower than the serial number on the master, the slave server will attempt to update its copy of the zone.

+

+ + +Setting the serial number to a lower number on the master server than the slave server means that the slave will not perform updates to its copy of the zone.

+

+ + +The solution to this is to add 2147483647 (2^31-1) to the number, reload the zone and make sure all slaves have updated to the new zone serial number, then reset the number to what you want it to be, and reload the zone again.

+
+
+
    +

    + + +8.3 Where Can I Get Help?

    +
+

+ + +The Internet Software Consortium (ISC) offers a wide range of support and service agreements for BIND and DHCP servers. Four levels of premium support are available and each level includes support for all ISC programs, significant discounts on products and training, and a recognized priority on bug fixes and non-funded feature requests. In addition, ISC offers a standard support agreement package which includes services ranging from bug fix announcements to remote support. It also includes training in BIND and DHCP.

+

+ + +To discuss arrangements for support, contact +info@isc.org + + +or visit the ISC web page at
-ftp://www.isi.edu/in-notes/RFCxxx.txt - (where -xxx - is the number of the RFC). RFCs are also available via the Web at -
-http://www.ietf.org/rfc/ -.

-
-

- - -C.1.1 Standards

-

- - -RFC974. Partridge, C. -Mail Routing and the Domain System -. January 1986.

-

- - -RFC1034. Mockapetris, P.V. -Domain Names - Concepts and Facilities -. P.V. November 1987.

-

- - -RFC1035. Mockapetris, P. V. -Domain Names - Implementation and Specification -. November 1987.

-
-
-

- - -C.1.2 - -Proposed Standards

-

- - -RFC2181. Elz, R., R. Bush. -Clarifications to the DNS Specification -. July 1997.

-

- - -RFC2308. Andrews, M. -Negative Caching of DNS Queries -. March 1998.

-

- - -RFC1995. Ohta, M. -Incremental Zone Transfer in DNS -. August 1996.

-

- - -RFC1996. Vixie, P. -A Mechanism for Prompt Notification of Zone Changes -. August 1996.

-

- - -RFC2136. Vixie, P., S. Thomson, Y. Rekhter, J. Bound. -Dynamic Updates in the Domain Name System -. April 1997.

-

- - -RFC2845. Vixie, P., O. Gudmundsson, D. Eastlake 3rd, B. Wellington. -Secret Key Transaction Authentication for DNS (TSIG) -. May 2000.

-
-
-

- - -C.1.3 Proposed Standards Still Under Development

-

- - - -Note: - the following list of RFCs are undergoing major revision by the IETF.

-

- - -RFC1886. Thomson, S., C. Huitema. -DNS Extensions to support IP version 6 -. S. December 1995.

-

- - -RFC2065. Eastlake, 3rd, D., C. Kaufman. -Domain Name System Security Extensions -. January 1997.

-

- - -RFC2137. Eastlake, 3rd, D. -Secure Domain Name System Dynamic Update -. April 1997.

-
-
-

- - -C.1.4 Other Important RFCs About DNS Implementation

-

- - -RFC1535. Gavron, E. -A Security Problem and Proposed Correction With Widely Deployed DNS Software. - October 1993.

-

- - -RFC1536. Kumar, A., J. Postel, C. Neuman, P. Danzig, S. Miller. -Common DNS Implementation Errors and Suggested Fixes -. October 1993.

-

- - -RFC1982. Elz, R., R. Bush. -Serial Number Arithmetic -. August 1996.

-
-
-

- - -C.1.5 Resource Record Types

-

- - -RFC1183. Everhart, C.F., L. A. Mamakos, R. Ullmann, P. Mockapetris. -New DNS RR Definitions -. October 1990.

-

- - -RFC1706. Manning, B., R. Colella. -DNS NSAP Resource Records -. October 1994.

-

- - -RFC2168. Daniel, R., M. Mealling. -Resolution of Uniform Resource Identifiers using the Domain Name System. June 1997. -

-

- - -RFC1876. Davis, C., P. Vixie, T. Goodwin, I. Dickinson. -A Means for Expressing Location Information in the Domain Name System -. January 1996.

-

- - -RFC2052. Gulbrandsen, A., P. Vixie. -A DNS RR for Specifying the Location of Services. - October 1996.

-

- - -RFC2163. Allocchio, A. U -sing the Internet DNS to Distribute MIXER Conformant Global Address Mapping -. January 1998.

-

- - -RFC2230. Atkinson, R. -Key Exchange Delegation Record for the DNS -. October 1997.

-
-
-

- - -C.1.6 DNS and the Internet

-

- - -RFC1101. Mockapetris, P. V. -DNS Encoding of Network Names and Other Types -. April 1989.

-

- - -RFC1123. Braden, R. -Requirements for Internet Hosts - Application and Support -. October 1989.

-

- - -RFC1591. Postel, J. D -omain Name System Structure and Delegation -. March 1994.

-

- - -RFC2317. Eidnes, H., G. de Groot, P. Vixie. -Classless IN-ADDR.ARPA Delegation -. March 1998.

-
-
-

- - -C.1.7 DNS Operations

-

- - -RFC1537. Beertema, P. -Common DNS Data File Configuration Errors -. October 1993.

-

- - -RFC1912. Barr, D. -Common DNS Operational and Configuration Errors -. February 1996.

-

- - -RFC2182. Elz, R. R. Bush, S. Bradner, M. Patton. -Selection and Operation of Secondary DNS Servers -. July 1997.

-

- - -RFC2219. Hamilton, M., R. Wright. -Use of DNS Aliases for Network Services. - October 1997.

-
-
-

- - -C.1.8 Other DNS-related RFCs

-

- - - -Note: - the following list of RFCs, although DNS-related, are not concerned with implementing software.

-

- - -RFC1464. Rosenbaum, R. -Using the Domain Name System To Store Arbitrary String Attributes -. May 1993.

-

- - -RFC1713. Romao, A. -Tools for DNS Debugging -. November 1994.

-

- - -RFC1794. Brisco, T. -DNS Support for Load Balancing -. April 1995.

-

- - -RFC2240. Vaughan, O. -A Legal Basis for Domain Name Allocation -. November1997.

-

- - -RFC2345. Klensin, J., T. Wolf, G. Oglesby. -Domain Names and Company Name Retrieval -. May 1998.

-

- - -RFC2352. Vaughan, O. -A Convention For Using Legal Names as Domain Names -. May 1998.

-
-
-

- - -C.1.9 Obsolete and Unimplemented Experimental RRs

-

- - -RFC1712. Farrell, C., M. Schulze, S. Pleitner, D. Baldoni. -DNS Encoding of Geographical Location -. November 1994.

-
-
-
-

- - -C.2 - -Internet Drafts

-

- - -Internet Drafts (IDs) are rough-draft working documents of the Internet Engineering Task Force. They are, in essence, RFCs in the preliminary stages of development. Implementors are cautioned not to regard IDs as archival, and they should not be quoted or cited in any formal documents unless accompanied by the disclaimer that they are "works in progress." IDs have a lifespan of six months after which they are deleted unless updated by their authors.

-
-
-

- - -C.3 Electronic Mail Communication

-

- - -Wellington, Brian (bwellington@tislabs.com). -DNSSEC usage document -. E-mail to David Conrad (David_Conrad@isc.org). 15 March 1999.

-

- - -Wellington, Brian (bwellington@tislabs.com). -TSIG guide for BIND 8.2+ -. E-mail to private mailing list (private communication). 22 April 1999.

-
-
-

- - -C.4 Other BIND Documents

-

- - -Albitz, Paul and Cricket Liu. 1998. -DNS and BIND -. Sebastopol, CA: O'Reilly and Associates.

-
+http://www.isc.org/services/support/ + to read more.

- +
+
+

Return to BIND 9 Administrator Reference Manual table of contents.

+ diff --git a/doc/arm/Bv9ARM.9.html b/doc/arm/Bv9ARM.9.html new file mode 100644 index 0000000000..2b3beff13a --- /dev/null +++ b/doc/arm/Bv9ARM.9.html @@ -0,0 +1,886 @@ + + + + + +Appendices + +
+
+ + +Appendices
+
+
+ + +Acknowledgements
+
+
+ + +A Brief History of the DNS and BIND
+

+ + +Although the "official" beginning of the Domain Name System occurred in 1984 with the publication of RFC 920, the core of the new system was described in 1983 in RFCs 882 and 883. From 1984 to 1987, the ARPAnet (the precursor to today's Internet) became a testbed of experimentation for developing the new naming/addressing scheme in an rapidly expanding, operational network environment. New RFCs were written and published in 1987 that modified the original documents to incorporate improvements based on the working model. RFC 1034, "Domain Names-Concepts and Facilities," and RFC 1035, "Domain Names-Implementation and Specification" were published and became the standards upon which all DNS implementations are built.

+

+ + +The first working domain name server, called "Jeeves," was written in 1983-84 by Paul Mockapetris for operation on DEC Tops-20 machines located at the University of Southern California's Information Sciences Institute (USC-ISI) and SRI International's Network Information Center (SRI-NIC). A DNS server for Unix machines, the Berkeley Internet Name Domain (BIND) package, was written soon after by a group of graduate students at the University of California at Berkeley under a grant from the US Defense Advanced Research Projects Administration (DARPA). Versions of BIND through 4.8.3 were maintained by the Computer Systems Research Group (CSRG) at UC Berkeley. Douglas Terry, Mark Painter, David Riggle and Songnian Zhou made up the initial BIND project team. After that, additional work on the software package was done by Ralph Campbell. Kevin Dunlap, a Digital Equipment Corporation employee on loan to the CSRG, worked on BIND for 2 years, from 1985 to 1987. Many other people also contributed to BIND development during that time: Doug Kingston, Craig Partridge, Smoot Carl-Mitchell, Mike Muuss, Jim Bloom and Mike Schwartz. BIND maintenance was subsequently handled by Mike Karels and O. Kure.

+

+ + +BIND versions 4.9 and 4.9.1 were released by Digital Equipment Corporation (now Compaq Computer Corporation). Paul Vixie, then a DEC employee, became BIND's primary caretaker. Paul was assisted by Phil Almquist, Robert Elz, Alan Barrett, Paul Albitz, Bryan Beecher, Andrew Partan, Andy Cherenson, Tom Limoncelli, Berthold Paffrath, Fuat Baran, Anant Kumar, Art Harkin, Win Treese, Don Lewis, Christophe Wolfhugel, and others.

+

+ + +BIND Version 4.9.2 was sponsored by Vixie Enterprises. Paul Vixie became BIND's principal architect/programmer.

+

+ + +BIND versions from 4.9.3 onward have been developed and maintained by the Internet Software Consortium with support being provided by ISC's sponsors. As co-architects/programmers, Bob Halley and Paul Vixie released the first production-ready version of BIND version 8 in May 1997.

+

+ + +BIND development work is made possible today by the sponsorship of several corporations, and by the tireless work efforts of numerous individuals.

+
+
+
+
+ + + + +Historical DNS Information
+
+
+ + + + +Classes of Resource Records
+
+
+ + +HS = hesiod
+

+ + +The +hesiod +class is an information service developed by MIT's Project Athena. It is used to share information about various systems databases, such as users, groups, printers and so on. The keyword +hs + is a synonym for hesiod.

+
+
+
+ + +CH = chaos
+

+ + +The +chaos + class is used to specify zone data for the MIT-developed CHAOSnet, a LAN protocol created in the mid-1970s.

+
+
+
+
+
+ + +General DNS Reference Information
+
+
+ + +IPv6 addresses (A6)
+

+ + +IPv6 addresses are 128-bit identifiers for interfaces and sets of interfaces which were introduced in the DNS to facilitate scalable Internet routing. There are three types of addresses: +Unicast +, an identifier for a single interface; +Anycast +, an identifier for a set of interfaces; and +Multicast +, an identifier for a set of interfaces. Here we describe the global Unicast address scheme. For more information, see RFC 2374.

+

+ + +The aggregatable global Unicast address format is as follows:

+

+ + + 

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + +3

+		 +

+ + +13

+		 +

+ + +8

+		 +

+ + +24

+		 +

+ + +16

+		 +

+ + +64 bits

+
+

+ + +FP

+		 +

+ + +TLA ID

+		 +

+ + +RES

+		 +

+ + +NLA ID

+		 +

+ + +SLA ID

+		 +

+ + +Interface ID

+
+

+ + +<------ Public Topology ------>

+		 +

+ + + 

+		 +

+ + + 

+
+

+ + + 

+		 +

+ + + 

+		 +

+ + + 

+		 +

+ + + 

+		 +

+ + +<-Site Topology->

+		 +

+ + + 

+
+

+ + + 

+		 +

+ + + 

+		 +

+ + + 

+		 +

+ + + 

+		 +

+ + + 

+		 +

+ + +<------ Interface Identifier ------>

+
+

+ + +Where

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

+ + +FP

+		 +

+ + +=

+		 +

+ + +Format Prefix (001)

+
+

+ + +TLA ID

+		 +

+ + +=

+		 +

+ + +Top-Level Aggregation Identifier

+
+

+ + +RES

+		 +

+ + +=

+		 +

+ + +Reserved for future use

+
+

+ + +NLA ID

+		 +

+ + +=

+		 +

+ + +Next-Level Aggregation Identifier

+
+

+ + +SLA ID

+		 +

+ + +=

+		 +

+ + +Site-Level Aggregation Identifier

+
+

+ + +INTERFACE ID

+		 +

+ + +=

+		 +

+ + +Interface Identifier

+
+

+ + +The +Public Topology + is provided by the upstream provider or ISP, and (roughly) corresponds to the IPv4 +network + section of the address range. The +Site Topology + is where you can subnet this space, much the same as subnetting an IPv4 class A or B network into class Cs. The +Interface Identifier + is the address of an individual interface on a given network. (With IPv6, addresses belong to interfaces rather than machines.)

+

+ + +The subnetting capability of IPv6 is much more flexible than that of IPv4: subnetting can now be carried out on bit boundaries, in much the same way as Classless InterDomain Routing (CIDR).

+

+ + +The internal structure of the Public Topology for an A6 global unicast address consists of:

+

+ + + 

+ + + + + + + + + + + + + +
+

+ + +3

+		 +

+ + +13

+		 +

+ + +8

+		 +

+ + +24

+
+

+ + +FP

+		 +

+ + +TLA ID

+		 +

+ + +RES

+		 +

+ + +NLA ID

+
+

+ + +A 3 bit FP (Format Prefix) of 001 indicates this is a global Unicast address. FP lengths for other types of addresses may vary.

+

+ + +13 TLA (Top Level Aggregator) bits give the prefix of your top-level IP backbone carrier.

+

+ + +8 Reserved bits

+

+ + +24 bits for Next Level Aggregators. This allows organizations with a TLA to hand out portions of their IP space to client organizations, so that the client can then split up the network further by filling in more NLA bits, and hand out IPv6 prefixes to their clients, and so forth.

+

+ + +There is no particular structure for the Site topology section. Organizations can allocate these bits in any way they desire, in the same way as they would subnet an IPv4 class A (8-bit prefix) network.

+

+ + +The Interface Identifier must be unique on that network. On ethernet networks, one way to ensure this is to set the address to the first three bytes of the hardware address, "FFFE", then the last three bytes of the hardware address. The lowest significant bit of the first byte should then be complemented. Addresses are written as 32-bit blocks separated with a colon, and leading zeros of a block may be omitted, for example:

+

+ + + +3ffe:8050:201:9:a00:20ff:fe81:2b32 +

+

+ + +IPv6 address specifications are likely to contain long strings of zeros, so the architects have included a shorthand for specifying them. The double colon (`::') indicates the longest possible string of zeros that can fit, and can be used only once in an address.

+
+
+
+
+ + + + +Bibliography (and Suggested Reading)
+
+
+ + + + +Request for Comments (RFCs)
+

+ + +Specification documents for the Internet protocol suite, including the DNS, are published as part of the Request for Comments (RFCs) series of technical notes. The standards themselves are defined by the Internet Engineering Task Force (IETF) and the Internet Engineering Steering Group (IESG). RFCs can be obtained online via FTP at
+ +ftp://www.isi.edu/in-notes/RFCxxx.txt + (where +xxx + is the number of the RFC). RFCs are also available via the Web at +http://www.ietf.org/rfc/ +.

+
+
+ + +Standards
+

+ + +RFC974. Partridge, C. +Mail Routing and the Domain System +. January 1986.

+

+ + +RFC1034. Mockapetris, P.V. +Domain Names - Concepts and Facilities +. P.V. November 1987.

+

+ + +RFC1035. Mockapetris, P. V. +Domain Names - Implementation and Specification +. November 1987.

+
+
+
+ + + + +Proposed Standards
+

+ + +RFC2181. Elz, R., R. Bush. +Clarifications to the DNS Specification +. July 1997.

+

+ + +RFC2308. Andrews, M. +Negative Caching of DNS Queries +. March 1998.

+

+ + +RFC1995. Ohta, M. +Incremental Zone Transfer in DNS +. August 1996.

+

+ + +RFC1996. Vixie, P. +A Mechanism for Prompt Notification of Zone Changes +. August 1996.

+

+ + +RFC2136. Vixie, P., S. Thomson, Y. Rekhter, J. Bound. +Dynamic Updates in the Domain Name System +. April 1997.

+

+ + +RFC2845. Vixie, P., O. Gudmundsson, D. Eastlake 3rd, B. Wellington. +Secret Key Transaction Authentication for DNS (TSIG) +. May 2000.

+
+
+
+ + +Proposed Standards Still Under Development
+

+ + + +Note: the following list of RFCs are undergoing major revision by the IETF.

+

+ + +RFC1886. Thomson, S., C. Huitema. +DNS Extensions to support IP version 6 +. S. December 1995.

+

+ + +RFC2065. Eastlake, 3rd, D., C. Kaufman. +Domain Name System Security Extensions +. January 1997.

+

+ + +RFC2137. Eastlake, 3rd, D. +Secure Domain Name System Dynamic Update +. April 1997.

+
+
+
+ + +Other Important RFCs About DNS Implementation
+

+ + +RFC1535. Gavron, E. +A Security Problem and Proposed Correction With Widely Deployed DNS Software. + October 1993.

+

+ + +RFC1536. Kumar, A., J. Postel, C. Neuman, P. Danzig, S. Miller. +Common DNS Implementation Errors and Suggested Fixes +. October 1993.

+

+ + +RFC1982. Elz, R., R. Bush. +Serial Number Arithmetic +. August 1996.

+
+
+
+ + +Resource Record Types
+

+ + +RFC1183. Everhart, C.F., L. A. Mamakos, R. Ullmann, P. Mockapetris. +New DNS RR Definitions +. October 1990.

+

+ + +RFC1706. Manning, B., R. Colella. +DNS NSAP Resource Records +. October 1994.

+

+ + +RFC2168. Daniel, R., M. Mealling. +Resolution of Uniform Resource Identifiers using the Domain Name System. June 1997. +

+

+ + +RFC1876. Davis, C., P. Vixie, T. Goodwin, I. Dickinson. +A Means for Expressing Location Information in the Domain Name System +. January 1996.

+

+ + +RFC2052. Gulbrandsen, A., P. Vixie. +A DNS RR for Specifying the Location of Services. + October 1996.

+

+ + +RFC2163. Allocchio, A. U +sing the Internet DNS to Distribute MIXER Conformant Global Address Mapping +. January 1998.

+

+ + +RFC2230. Atkinson, R. +Key Exchange Delegation Record for the DNS +. October 1997.

+
+
+
+ + +DNS and the Internet
+

+ + +RFC1101. Mockapetris, P. V. +DNS Encoding of Network Names and Other Types +. April 1989.

+

+ + +RFC1123. Braden, R. +Requirements for Internet Hosts - Application and Support +. October 1989.

+

+ + +RFC1591. Postel, J. D +omain Name System Structure and Delegation +. March 1994.

+

+ + +RFC2317. Eidnes, H., G. de Groot, P. Vixie. +Classless IN-ADDR.ARPA Delegation +. March 1998.

+
+
+
+ + +DNS Operations
+

+ + +RFC1537. Beertema, P. +Common DNS Data File Configuration Errors +. October 1993.

+

+ + +RFC1912. Barr, D. +Common DNS Operational and Configuration Errors +. February 1996.

+

+ + +RFC1912. Barr, D. +Common DNS Operational and Configuration Errors +. February 1996.

+

+ + +RFC2010. Manning, B., P. Vixie. +Operational Criteria for Root Name Servers. + October 1996.

+

+ + +RFC2219. Hamilton, M., R. Wright. +Use of DNS Aliases for Network Services. + October 1997.

+
+
+
+ + +Other DNS-related RFCs
+
+
+
+
+
+

+ + + +Note: the following list of RFCs, although DNS-related, are not concerned with implementing software.

+

+ + +RFC1464. Rosenbaum, R. +Using the Domain Name System To Store Arbitrary String Attributes +. May 1993.

+

+ + +RFC1713. Romao, A. +Tools for DNS Debugging +. November 1994.

+

+ + +RFC1794. Brisco, T. +DNS Support for Load Balancing +. April 1995.

+

+ + +RFC2240. Vaughan, O. +A Legal Basis for Domain Name Allocation +. November1997.

+

+ + +RFC2345. Klensin, J., T. Wolf, G. Oglesby. +Domain Names and Company Name Retrieval +. May 1998.

+

+ + +RFC2352. Vaughan, O. +A Convention For Using Legal Names as Domain Names +. May 1998.

+
+
+ + +Obsolete and Unimplemented Experimental RRs
+

+ + +RFC1712. Farrell, C., M. Schulze, S. Pleitner, D. Baldoni. +DNS Encoding of Geographical Location +. November 1994.

+
+
+
+ + + + +Internet Drafts
+

+ + +Internet Drafts (IDs) are rough-draft working documents of the Internet Engineering Task Force. They are, in essence, RFCs in the preliminary stages of development. Implementors are cautioned not to regard IDs as archival, and they should not be quoted or cited in any formal documents unless accompanied by the disclaimer that they are "works in progress." IDs have a lifespan of six months after which they are deleted unless updated by their authors.

+
+
+
+ + +Other BIND Documents
+
+ +Albitz, Paul and Cricket Liu. 1998. +DNS and BIND +. Sebastopol, CA: O'Reilly and Associates.

+ +
+

Return to BIND 9 Administrator Reference Manual table of contents.

+ +
+
+
+ + diff --git a/doc/arm/Bv9ARM.css b/doc/arm/Bv9ARM.css index 74258efda5..21c7aebe23 100644 --- a/doc/arm/Bv9ARM.css +++ b/doc/arm/Bv9ARM.css @@ -1,22 +1,3 @@ -/* - * Copyright (C) 2000 Internet Software Consortium. - * - * Permission to use, copy, modify, and distribute this software for any - * purpose with or without fee is hereby granted, provided that the above - * copyright notice and this permission notice appear in all copies. - * - * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS - * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE - * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL - * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR - * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS - * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS - * SOFTWARE. - */ - -/* $Id: Bv9ARM.css,v 1.4 2000/06/22 21:53:47 tale Exp $ */ - A:link { color: blue; text-decoration: underline; @@ -148,7 +129,7 @@ PRE.2Level-fixed1 { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 63.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #000000; @@ -228,7 +209,7 @@ PRE.3Level-fixed { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 99.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: medium; font-style: Regular; color: #000000; @@ -244,7 +225,7 @@ P.3Level-fixed-special { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 99.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: medium; font-style: Regular; color: #000000; @@ -260,7 +241,7 @@ P.3Level-fixed1 { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 99.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: medium; font-style: Regular; color: #000000; @@ -276,7 +257,7 @@ P.3Level-fixed2 { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 99.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #000000; @@ -324,7 +305,7 @@ P.3LevelContinued21 { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 99.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #000000; @@ -381,22 +362,6 @@ LI.4Level-bullet2 { text-transform: none; font-family: Times; } -H1.4Level-bullet21, H2.4Level-bullet21, H3.4Level-bullet21, H4.4Level-bullet21, H5.4Level-bullet21, H6.4Level-bullet21 { - text-align: left; 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- font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #000000; @@ -452,7 +417,7 @@ PRE.4Level-fixedSmall { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 126.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: medium; font-style: Regular; color: #000000; @@ -484,7 +449,7 @@ H1.4LevelContinued1, H2.4LevelContinued1, H3.4LevelContinued1, H4.4LevelContinue margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 144.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #000000; @@ -635,7 +600,7 @@ P.Biblio { text-decoration: none; vertical-align: baseline; text-transform: none; - font-family: Times New Roman; + font-family: Times; } P.Body { text-align: left; @@ -685,6 +650,22 @@ P.Body11 { text-transform: none; font-family: Courier; } +LI.Bulleted { + text-align: left; + text-indent: -18.000000pt; + margin-top: 0.000000pt; + margin-bottom: 0.000000pt; 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+ margin-right: 0.000000pt; + margin-left: 0.000000pt; + font-size: 12.000000pt; + font-weight: Bold; + font-style: Regular; + color: #000000; + text-decoration: none; + vertical-align: baseline; + text-transform: none; + font-family: Times; +} +H1.HeadingRunIn, H2.HeadingRunIn, H3.HeadingRunIn, H4.HeadingRunIn, H5.HeadingRunIn, H6.HeadingRunIn { + text-align: left; + text-indent: 0.000000pt; + margin-top: 6.000000pt; + margin-bottom: 0.000000pt; + margin-right: 0.000000pt; + margin-left: 0.000000pt; + font-size: 12.000000pt; + font-weight: Bold; + font-style: Regular; + color: #000000; + text-decoration: none; + vertical-align: baseline; + text-transform: none; + font-family: Times; +} +P.Indented { + text-align: left; + text-indent: 0.000000pt; + margin-top: 0.000000pt; + margin-bottom: 0.000000pt; + margin-right: 0.000000pt; + margin-left: 18.000000pt; + font-size: 12.000000pt; + font-weight: medium; + font-style: Regular; + color: #000000; + text-decoration: none; + vertical-align: baseline; + text-transform: none; + font-family: Times; +} P.Mapping-Table-Cell { text-align: left; text-indent: 0.000000pt; @@ -1044,7 +1121,7 @@ P.Mapping-Table-Cell310 { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 0.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #ffffff; @@ -1140,7 +1217,7 @@ P.Mapping-Table-Cell316 { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 0.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #000000; @@ -1204,7 +1281,7 @@ P.Mapping-Table-Cell331 { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 0.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: medium; font-style: Regular; color: #ffffff; @@ -1316,7 +1393,7 @@ P.Mapping-Table-Cell381 { margin-bottom: 0.000000pt; margin-right: 0.000000pt; margin-left: 0.000000pt; - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: medium; 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} KBD.Literal-user-input { - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #000000; @@ -1519,7 +1660,7 @@ KBD.Literal-user-input { font-family: Courier New; } EM.Optional-meta-syntax { - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: medium; font-style: Italic; color: #000000; @@ -1542,8 +1683,8 @@ EM.pathname2 { font-style: Italic; font-family: Times; } -CODE.production_target { - font-size: 9.000000pt; +EM.production_target { + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #000000; @@ -1553,7 +1694,7 @@ CODE.production_target { font-family: Arial; } CODE.Program-Process { - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: Bold; font-style: Regular; color: #000000; @@ -1573,7 +1714,7 @@ EM.URL { font-family: Times; } EM.variable { - font-size: 9.000000pt; + font-size: 10.000000pt; font-weight: medium; font-style: Italic; color: #000000; diff --git a/doc/arm/Bv9ARM.html b/doc/arm/Bv9ARM.html index a8839d919e..e9fd9c50aa 100644 --- a/doc/arm/Bv9ARM.html +++ b/doc/arm/Bv9ARM.html @@ -1,46 +1,20 @@ - - - - -BINDv9 Administrator Reference Manual +BIND 9 Administrator Reference Manual -
-
ISC logo
-

BIND version 9
Administrator Reference Manual

-

DRAFT +

BIND 9
Administrator Reference Manual

+
June, 2000
-
-
-

Warning! This DRAFT document is the property of the Internet Software Consortium (ISC) and contains proprietary ISC information. The information in this document is subject to change.

- -
@@ -49,38 +23,44 @@ June, 2000
Table of Contents
+

    - + Section 1. Introduction

    - + Section 2. BIND Resource Requirements

    - + Section 3. Nameserver Configuration

    - + Section 4. Advanced Concepts

    - -Section 5. BINDv9 Configuration Reference + +Section 5. The BIND 9 Lightweight Resolver

    - -Section 6. Security Considerations + +Section 6. BIND 9 Configuration Reference

    - -Section 7. Troubleshooting + +Section 7. BIND 9 Security Considerations

    -Appendices + +Section 8. Troubleshooting

    - +

    + +Section 9. Appendices +

    +
Copyright ©2000 Internet Software Consortium diff --git a/doc/arm/Bv9ARM.txt b/doc/arm/Bv9ARM.txt index 10463855dd..1b435e2c7e 100644 --- a/doc/arm/Bv9ARM.txt +++ b/doc/arm/Bv9ARM.txt @@ -1,471 +1,477 @@ -Copyright (C) 2000 Internet Software Consortium. -See COPYRIGHT in the source root or http://www.isc.org/copyright for terms. +BIND 9 Administrator Reference Manual +June 2000 +Copyright (c) 2000 Internet Software Consortium -$Id: Bv9ARM.txt,v 1.3 2000/06/22 21:53:50 tale Exp $ +-------------------------------------------------------------------- - BIND version 9 - Administrator Reference Manual - June 2000 - DRAFT - - Copyright (c) 2000 Internet Software Consortium - - ------------------------------------------------------------ - - Table of Contents +Table of Contents Section 1 : Introduction -Scope of Document -Organization of This Document -Conventions Used in This Document -Discussion of Domain Name System (DNS) Basics and BIND -Nameservers -Types of Zones -Servers -Master Server -Slave Server -Caching Only Server -Forwarding Server -Stealth Server +1.1 Scope of Document +1.2 Organization of This Document +1.3 Conventions Used in This Document +1.4 Discussion of Domain Name System (DNS) Basics and BIND +1.4.1 Nameservers +1.4.2 Types of Zones +1.4.3 Servers +1.4.3.1 Master Server +1.4.3.2 Slave Server +1.4.3.3 Caching Only Server +1.4.3.4 Forwarding Server +1.4.3.5 Stealth Server Section 2 : BIND Resource Requirements -Hardware requirements -CPU Requirements -Memory Requirements -Nameserver Intensive Environment Issues -Operating Systems Supported by the Internet Software Consortium +2.1 Hardware requirements +2.2 CPU Requirements +2.3 Memory Requirements +2.4 Nameserver Intensive Environment Issues +2.5 Supported Operating Systems Section 3 : Nameserver Configuration -Sample Configuration and Logging -Load Balancing and Round Robin -Notify -Nameserver Operations -Tools for Use With the Nameserver Daemon -Diagnostic Tools -Administrative Tools +3.1 Sample Configurations +3.1.1 A Caching-only Nameserver +3.1.2 An Authoritative-only Nameserver +3.2 Load Balancing +3.3 Notify +3.4 Nameserver Operations +3.4.1 Tools for Use With the Nameserver Daemon +3.4.1.1 Diagnostic Tools +3.4.1.2 Administrative Tools Section 4 : Advanced Concepts -Dynamic Update -Incremental Zone Transfers (IXFR) -Split DNS -TSIG -Generate Shared Keys for Each Pair of Hosts -Automatic Generation -Manual Generation -Copying the Shared Secret to Both Machines -Informing the Servers of the Key's Existence -Instructing the Server to Use the Key -TSIG Key Based Access Control -Errors -TKEY -DNSSEC -Generating Keys -Creating a Keyset -Signing the Child's Keyset -Signing the Zone -Configuring Servers -IPv6 -IPv6 addresses (A6) -Name to Address Lookup -Address to Name Lookup -Using DNAME for Delegation of IPv6 Reverse Addresses +4.1 Dynamic Update +4.2 Incremental Zone Transfers (IXFR) +4.3 Split DNS +4.4 TSIG +4.4.1 Generate Shared Keys for Each Pair of Hosts +4.4.1.1 Automatic Generation +4.4.1.2 Manual Generation +4.4.2 Copying the Shared Secret to Both Machines +4.4.3 Informing the Servers of the Key's Existence +4.4.4 Instructing the Server to Use the Key +4.4.5 TSIG Key Based Access Control +4.4.6 Errors +4.5 TKEY +4.6 SIG(0) +4.7 DNSSEC +4.7.1 Generating Keys +4.7.2 Creating a Keyset +4.7.3 Signing the Child's Keyset +4.7.4 Signing the Zone +4.7.5 Configuring Servers +4.8 IPv6 Support in BIND 9 +4.8.1 Address Lookups Using AAAA Records +4.8.2 Address Lookups Using A6 Records +4.8.2.1 A6 Chains +4.8.2.2 A6 Records for DNS Servers +4.8.3 Address to Name Lookups Using Nibble Format +4.8.4 Address to Name Lookups Using Bitstring Format +4.8.5 Using DNAME for Delegation of IPv6 Reverse Addresses -Section 5 : BINDv9 Configuration Reference +Section 5 : The BIND 9 Lightweight Resolver -Configuration file elements -Address Match Lists -Syntax -Definition and Usage -Comment Syntax -Syntax -Definition and Usage -Configuration File Grammar -acl Statement Grammar -acl Statement Definition and Usage -controls Statement Grammar -controls Statement Definition and Usage -include Statement Grammar -include Statement Definition and Usage -key Statement Grammar -key Statement Definition and Usage -logging Statement Grammar -logging Statement Definition and Usage -The channel Phrase -The category Phrase -options Statement Grammar -options Statement Definition and Usage -Boolean Options -Forwarding -Name Checking -Access Control -Interfaces -Query Address -Zone Transfers -Resource Limits -Periodic Task Intervals -Topology -The sortlist Statement -RRset Ordering -Tuning -Deprecated Features -server Statement Grammar -server Statement Definition and Usage -trusted-keys Statement Grammar -trusted-keys Statement Definition and Usage -view Statement Grammar -view Statement Definition and Usage -zone Statement Grammar -zone Statement Definition and Usage -Zone Types -Class -Zone Options -Dynamic Update Policies -Zone File -Types of Resource Records and When to Use Them -Resource Records -Textual expression of RRs -Discussion of MX Records -Setting TTLs -Inverse Mapping in IPv4 -Other Zone File Directives -The $ORIGIN Directive -The $INCLUDE Directive -The $TTL Directive -BIND Master File Extension: the $GENERATE Directive -Signals +5.1 The Lightweight Resolver Library +5.2 Running a Resolver Daemon -Section 6 : Security Considerations +Section 6 : BIND 9 Configuration Reference -Access Control Lists -chroot and setuid (for UNIX servers) -The chroot Environment -Using the setuid Function -Dynamic Update +6.1 Configuration File Element +6.1.1 Address Match Lists +6.1.1.1 Syntax +6.1.1.2 Definition and Usage +6.1.2 Comment Syntax +6.1.2.1 Syntax +6.1.2.2 Definition and Usage +6.2 Configuration File Grammar +6.2.1 acl Statement Grammar +6.2.2 acl Statement Definition and Usage +6.2.3 controls Statement Grammar +6.2.4 controls Statement Definition and Usage +6.2.5 include Statement Grammar +6.2.6 include Statement Definition and Usage +6.2.7 key Statement Grammar +6.2.8 key Statement Definition and Usage +6.2.9 logging Statement Grammar +6.2.10 logging Statement Definition and Usage +6.2.10.1 The channel Phrase +6.2.10.2 The category Phrase +6.2.11 options Statement Grammar +6.2.12 options Statement Definition and Usage +6.2.12.1 Boolean Options +6.2.12.2 Forwarding +6.2.12.3 Name Checking +6.2.12.4 Access Control +6.2.12.5 Interfaces +6.2.12.6 Query Address +6.2.12.7 Zone Transfers +6.2.12.8 Resource Limits +6.2.12.9 Periodic Task Intervals +6.2.12.10 Topology +6.2.12.11 The sortlist Statement +6.2.12.12 RRset Ordering +6.2.12.13 Tuning +6.2.12.14 Deprecated Features +6.2.13 server Statement Grammar +6.2.14 server Statement Definition and Usage +6.2.15 trusted-keys Statement Grammar +6.2.16 trusted-keys Statement Definition and Usage +6.2.17 view Statement Grammar +6.2.18 view Statement Definition and Usage +6.2.19 zone Statement Grammar +6.2.20 zone Statement Definition and Usage +6.2.20.1 Zone Types +6.2.20.2 Class +6.2.20.3 Zone Options +6.2.20.4 Dynamic Update Policies +6.3 Zone File +6.3.1 Types of Resource Records and When to Use Them +6.3.1.1 Resource Records +6.3.1.2 Textual expression of RRs +6.3.2 Discussion of MX Records +6.3.3 Setting TTLs +6.3.4 Inverse Mapping in IPv4 +6.3.5 Other Zone File Directives +6.3.5.1 The $ORIGIN Directive +6.3.5.2 The $INCLUDE Directive +6.3.5.3 The $TTL Directive +6.3.6 BIND Master File Extension: the $GENERATE Directive +6.3.7 Signals 69 -Section 7 : Troubleshooting +Section 7 : BIND 9 Security Considerations -Common Log Messages and What They Mean -Common Problems -It's not working; how can I figure out what's wrong? -Incrementing and Changing the Serial Number -Where Can I Get Help? +7.1 Access Control Lists +7.2 chroot and setuid (for UNIX servers) +7.2.1 The chroot Environment +7.2.2 Using the setuid Function +7.3 Dynamic Updates + +Section 8 : Troubleshooting + +8.1 Common Problems +8.1.1 It's not working; how can I figure out what's wrong? +8.2 Incrementing and Changing the Serial Number +8.3 Where Can I Get Help? Appendix A: Acknowledgements -A Brief History of the DNS and BIND + +A.1 A Brief History of the DNS and BIND Appendix B: Historical DNS Information -Classes of Resource Records -HS = hesiod -CH = chaos -Appendix C: Bibliography (and Suggested Reading) -Request for Comments (RFCs) -Standards -Proposed Standards -Proposed Standards Still Under Development -Other Important RFCs About DNS Implementation -Resource Record Types -DNS and the Internet -DNS Operations -Other DNS-related RFCs -Obsolete and Unimplemented Experimental RRs -Internet Drafts -Electronic Mail Communication -Other BIND Documents +B.1 Classes of Resource Records +B.1.1 HS = hesiod +B.1.2 CH = chaos - ------------------------------------------------------------ +Appendix C: General DNS Reference Information + +C.1 IPv6 addresses (A6) + +Appendix D: Bibliography (and Suggested Reading) + +D.1 Request for Comments (RFCs) +D.1.1 Standards +D.1.2 Proposed Standards +D.1.3 Proposed Standards Still Under Development +D.1.4 Other Important RFCs About DNS Implementation +D.1.5 Resource Record Types +D.1.6 DNS and the Internet +D.1.7 DNS Operations +D.1.8 Other DNS-related RFCs +D.1.9 Obsolete and Unimplemented Experimental RRs +D.2 Internet Drafts +D.3 Other BIND Documents + +-------------------------------------------------------------------- -Section 1. Introduction -The Internet Domain Name System (DNS) consists of the syntax to specify the names of entities in -the Internet in a hierarchical manner, the rules used for delegating authority over names, and the -system implementation that actually maps names to Internet addresses. DNS data is maintained in -a group of distributed hierarchical databases. -1.1 Scope of Document + Section 1. Introduction -The Berkeley Internet Name Domain (BIND) implements an Internet nameserver for a -number of operating systems. This document provides basic information about the -installation and care of the Internet Software Consortium (ISC) BIND version 9 software -package for system administrators. +The Internet Domain Name System (DNS) consists of the syntax to specify the +names of entities in the Internet in a hierarchical manner, the rules used +for delegating authority over names, and the system implementation that +actually maps names to Internet addresses. DNS data is maintained in a group +of distributed hierarchical databases. -1.2 Organization of This Document + 1.1 Scope of Document -In this document, Section 1 introduces the basic DNS and BIND concepts. Section 2 -describes resource requirements for running BIND in various environments. Information in -Section 3 is task-oriented in its presentation and is organized functionally, to aid in the -process of installing the BINDv9 software. The task-oriented section is followed by Section -4, which contains more advanced concepts that the system administrator may need for -implementing certain options. The contents of Section 5 are organized as in a reference -manual to aid in the ongoing maintenance of the software. Section 6 addresses security -considerations, and Section 7 contains troubleshooting help. The main body of the document -is followed by several Appendices which contain useful reference information, such as a -Glossary and a Bibliography, as well as historic information related to BIND and the -Domain Name System. +The Berkeley Internet Name Domain (BIND) implements an Internet nameserver +for a number of operating systems. This document provides basic information +about the installation and care of the Internet Software Consortium (ISC) +BIND version 9 software package for system administrators. -1.3 Conventions Used in This Document + 1.2 Organization of This Document + +In this document, Section 1 introduces the basic DNS and BIND concepts. +Section 2 describes resource requirements for running BIND in various +environments. Information in Section 3 is task-oriented in its presentation +and is organized functionally, to aid in the process of installing the +BIND 9 software. The task-oriented section is followed by Section 4 , which +contains more advanced concepts that the system administrator may need for +implementing certain options. Section 5 describes the BIND 9 lightweight +resolver. The contents of Section 6 are organized as in a reference manual +to aid in the ongoing maintenance of the software. Section 7 addresses +security considerations, and Section 8 contains troubleshooting help. The +main body of the document is followed by several Appendices which contain +useful reference information, such as a Bibliography and historic +information related to BIND and the Domain Name System. + + 1.3 Conventions Used in This Document In this document, we use the following general typographic conventions: -To describe: - We use the style: + To describe: We use the style: + a pathname, filename, URL, hostname, + mailing list name, or new term or conceptItalic + literal user input Fixed Width Bold + variable user input Fixed Width Italic + program output Fixed Width -a pathname, filename, URL, hostname, -mailing list name, or new term or concept - Italic +The following conventions are used in descriptions of the BIND configuration +file: -literal user input - Fixed Width Bold + To describe: We use the style: + keywords Sans Serif Bold -variable user input - Fixed Width Italic + variables Sans Serif Italic -program output - Fixed Width + "meta-syntactic" information (within brackets + when optional) Fixed Width Italic + Command line input Fixed Width Bold + Program output Fixed Width + Optional input Text is enclosed in square + brackets -The following conventions are used in descriptions of the BIND configuration file: + 1.4 Discussion of Domain Name System (DNS) Basics and BIND -To describe: - We use the style: +The purpose of this document is to explain the installation and basic upkeep +of the BIND software package, and we begin by reviewing the fundamentals of +the domain naming system as they relate to BIND. BIND consists of a +nameserver (or "daemon") called named and a resolver library. The BIND +server runs in the background, servicing queries on a well known network +port. The standard port for the User Datagram Protocol (UDP) and +Transmission Control Protocol (TCP), usually port 53, is specified in +/etc/services . The resolver is a set of routines residing in a system +library that provides the interface that programs can use to access the +domain name services. -keywords - Sans Serif Bold + 1.4.1 Nameservers -variables - Sans Serif Italic +A nameserver (NS) is a program that stores information about named resources +and responds to queries from programs called resolvers which act as client +processes. The basic function of an NS is to provide information about +network objects by answering queries. -"meta-syntactic" information (within brackets -when optional) - Fixed Width Italic - -Command line input - Fixed Width Bold - -Program output - Fixed Width - -Optional input - Text is enclosed in square brackets - - -1.4 Discussion of Domain Name System (DNS) Basics and BIND - -The purpose of this document is to explain the installation and basic upkeep of the BIND -software package, and we begin by reviewing the fundamentals of the domain naming -system as they relate to BIND. BIND consists of a nameserver (or "daemon") called named -and a resolver library. The BIND server runs in the background, servicing queries on a -well known network port. The standard port for the User Datagram Protocol (UDP) and -Transmission Control Protocol (TCP), usually port 53, is specified in /etc/services. The -resolver is a set of routines residing in a system library that provides the interface that -programs can use to access the domain name services. - -1.4.1 Nameservers - -A nameserver (NS) is a program that stores information about named resources and -responds to queries from programs called resolvers which act as client processes. -The basic function of an NS is to provide information about network objects by -answering queries. - -With the nameserver, the network can be broken into a hierarchy of domains. The -name space is organized as a tree according to organizational or administrative -boundaries. Each node of the tree, called a domain, is given a label. The name of the -domain is the concatenation of all the labels of the domains from the root to the -current domain. This is represented in written form as a string of labels listed from -right to left and separated by dots. A label need only be unique within its domain. -The whole name space is partitioned into areas called zones, each starting at a -domain and extending down to the leaf domains or to domains where other zones -start. Zones usually represent administrative boundaries. For example, a domain +With the nameserver, the network can be broken into a hierarchy of domains. +The name space is organized as a tree according to organizational or +administrative boundaries. Each node of the tree, called a domain, is given +a label. The name of the domain is the concatenation of all the labels of +the domains from the root to the current domain. This is represented in +written form as a string of labels listed from right to left and separated +by dots. A label need only be unique within its domain. The whole name space +is partitioned into areas called zones , each starting at a domain and +extending down to the leaf domains or to domains where other zones start. +Zones usually represent administrative boundaries. For example, a domain name for a host at the company Example, Inc. would be: ourhost.example.com -where com is the top level domain to which ourhost.example.com belongs, example -is a subdomain of com, and ourhost is the name of the host. +where com is the top level domain to which ourhost.example.com belongs, +example is a subdomain of com , and ourhost is the name of the host. -The specifications for the domain nameserver are defined in the RFC 1034, RFC -1035 and RFC 974. These documents can be found in -/usr/src/etc/named/doc in 4.4BSD or are available via File Transfer Protocol (FTP) -from -ftp://www.isi.edu/in-notes/ or via the Web at http://www.ietf.org/rfc/. (See Appendix -C for complete information on finding and retrieving RFCs.) It is also recommended -that you read the related man pages: named and resolver. +The specifications for the domain nameserver are defined in the RFC 1034, +RFC 1035 and RFC 974. These documents can be found in +/usr/src/etc/named/doc in 4.4BSD or are available via File Transfer Protocol +(FTP) from +ftp://www.isi.edu/in-notes/ or via the Web at http://www.ietf.org/rfc/ . +(See Appendix C for complete information on finding and retrieving RFCs.) It +is also recommended that you read the related man pages: named and resolver +. -1.4.2 Types of Zones + 1.4.2 Types of Zones -As we stated previously, a zone is a point of delegation in the DNS tree. A zone -consists of those contiguous parts of the domain tree for which a domain server has -complete information and over which it has authority. It contains all domain names -from a certain point downward in the domain tree except those which are delegated -to other zones. A delegation point has one or more NS records in the parent zone, -which should be matched by equivalent NS records at the root of the delegated zone -(i.e., the "@" name in the zone file). +As we stated previously, a zone is a point of delegation in the DNS tree. A +zone consists of those contiguous parts of the domain tree for which a +domain server has complete information and over which it has authority. It +contains all domain names from a certain point downward in the domain tree +except those which are delegated to other zones. A delegation point has one +or more NS records in the parent zone, which should be matched by equivalent +NS records at the root of the delegated zone. -To properly operate a nameserver, it is important to understand the difference -between a zone and a domain. +To properly operate a nameserver, it is important to understand the +difference between a zone and a domain . -For instance, consider the example.com domain which includes names such as -host.aaa.example.com and host.bbb.example.com even though the example.com -zone includes only delegations for the aaa.example.com and bbb.example.com -zones. A zone can map exactly to a single domain, but could also include only part -of a domain, the rest of which could be delegated to other nameservers. Every name -in the DNS tree is a domain, even if it is terminal, that is, has no subdomains. Every -subdomain is a domain and every domain except the root is also a subdomain. The -terminology is not intuitive and we suggest that you read RFCs 1033, 1034 and 1035 -to gain a complete understanding of this difficult and subtle topic. +For instance, consider the example.com domain which includes names such as +host.aaa.example.com and host.bbb.example.com even though the example.com +zone includes only delegations for the aaa.example.com and bbb.example.com +zones. A zone can map exactly to a single domain, but could also include +only part of a domain, the rest of which could be delegated to other +nameservers. Every name in the DNS tree is a domain , even if it is terminal +, that is, has no subdomains . Every subdomain is a domain and every domain +except the root is also a subdomain. The terminology is not intuitive and we +suggest that you read RFCs 1033, 1034 and 1035 to gain a complete +understanding of this difficult and subtle topic. -Though BIND is a Domain Nameserver, it deals primarily in terms of zones. The -primary and secondary declarations in the named.conf file specify zones, not -domains. When you ask some other site if it is willing to be a secondary server for -your domain, you are actually asking for secondary service for some collection of -zones. +Though BIND is a Domain Nameserver, it deals primarily in terms of zones. +The master and slave declarations in the named.conf file specify zones, not +domains. When you ask some other site if it is willing to be a slave server +for your domain , you are actually asking for slave service for some +collection of zones. -Each zone will have one primary master (also called primary) server which loads -the zone contents from some local file edited by humans or perhaps generated -mechanically from some other local file which is edited by humans. There there will -be some number of slave (also called secondary) servers, which load the zone -contents using the DNS protocol (that is, the secondary servers will contact the -primary and fetch the zone data using TCP). This set of servers-the primary and all -of its secondaries-should be listed in the NS records in the parent zone and will -constitute a delegation. This set of servers must also be listed in the zone file itself, -usually under the @ name which indicates the top level or root of the current zone. -You can list servers in the zone's top-level @ NS records that are not in the parent's -NS delegation, but you cannot list servers in the parent's delegation that are not -present in the zone's @. +Each zone will have one primary master (also called primary ) server which +loads the zone contents from some local file edited by humans or perhaps +generated mechanically from some other local file which is edited by humans. +There there will be some number of slave (also called secondary) servers, +which load the zone contents using the DNS protocol (that is, the secondary +servers will contact the primary and fetch the zone data using TCP). This +set of servers--the primary and all of its secondaries--should be listed in +the NS records in the parent zone and will constitute a delegation . This +set of servers must also be listed in the zone file itself, usually under +the @ name which indicates the top level or root of the current zone. You +can list servers in the zone's top-level @ NS records that are not in the +parent's NS delegation, but you cannot list servers in the parent's +delegation that are not present in the zone's @ . -Any servers listed in the NS records must be configured as authoritative for the -zone. A server is authoritative for a zone when it has been configured to answer -questions for that zone with authority, which it does by setting the "authoritative -answer" (AA) bit in reply packets. A server may be authoritative for more than one -zone. The authoritative data for a zone is composed of all of the Resource Records -(RRs)-the data associated with names in a tree-structured name space-attached to -all of the nodes from the top node of the zone down to leaf nodes or nodes above -cuts around the bottom edge of the zone. +Any servers listed in the NS records must be configured as authoritative for +the zone. A server is authoritative for a zone when it has been configured +to answer questions for that zone with authority, which it does by setting +the "authoritative answer" (AA) bit in reply packets. A server may be +authoritative for more than one zone. The authoritative data for a zone is +composed of all of the Resource Records (RRs)--the data associated with +names in a tree-structured name space--attached to all of the nodes from the +top node of the zone down to leaf nodes or nodes above cuts around the +bottom edge of the zone. -Adding a zone as a type master or type slave will tell the server to answer questions -for the zone authoritatively. If the server is able to load the zone into memory -without any errors it will set the AA bit when it replies to queries for the zone. See -RFCs 1034 and 1035 for more information about the AA bit. +Adding a zone as a type master or type slave will tell the server to answer +questions for the zone authoritatively. If the server is able to load the +zone into memory without any errors it will set the AA bit when it replies +to queries for the zone. See RFCs 1034 and 1035 for more information about +the AA bit. -1.4.3 Servers + 1.4.3 Servers -A DNS server can be master for some zones and slave for others or can be only a -master, or only a slave, or can serve no zones and just answer queries via its cache. -Master servers are often also called primaries and slave servers are often also called -secondaries. Both master/primary and slave/secondary servers are authoritative for a -zone. +A DNS server can be master for some zones and slave for others or can be +only a master, or only a slave, or can serve no zones and just answer +queries via its cache . Master servers are often also called primaries and +slave servers are often also called secondaries . Both master/primary and +slave/secondary servers are authoritative for a zone. -All servers keep data in their cache until the data expires, based on a Time To Live -(TTL) field which is maintained for all resource records. +All servers keep data in their cache until the data expires, based on a Time +To Live (TTL) field which is maintained for all resource records. -1.4.3.1 Master Server + 1.4.3.1 Master Server -The primary master server is the ultimate source of information about a -domain. The primary master is an authoritative server configured to be the -source of zone transfer for one or more secondary servers. The primary +The primary master server is the ultimate source of information about a +domain. The primary master is an authoritative server configured to be the +source of zone transfer for one or more secondary servers. The primary master server obtains data for the zone from a file on disk. -1.4.3.2 Slave Server + 1.4.3.2 Slave Server -A slave server, also called a secondary server, is an authoritative server -that uses zone transfers from the primary master server to retrieve the -zone data. Optionally, the slave server obtains zone data from a cache on -disk. Slave servers provide necessary redundancy. All secondary/slave -servers are named in the NS RRs for the zone. +A slave server , also called a secondary server , is an authoritative server +that uses zone transfers from the primary master server to retrieve the zone +data. Optionally, the slave server obtains zone data from a cache on disk. +Slave servers provide necessary redundancy. All secondary/slave servers are +named in the NS RRs for the zone. -1.4.3.3 Caching Only Server + 1.4.3.3 Caching Only Server -Some servers are caching only servers. This means that the server caches -the information that it receives and uses it until the data expires. A -caching only server is a server that is not authoritative for any zone. This -server services queries and asks other servers, who have the authority, for +Some servers are caching only servers . This means that the server caches +the information that it receives and uses it until the data expires. A +caching only server is a server that is not authoritative for any zone. This +server services queries and asks other servers, who have the authority, for the information it needs. -1.4.3.4 Forwarding Server + 1.4.3.4 Forwarding Server -Instead of interacting with the nameservers for the root and other -domains, a forwarding server always forwards queries it cannot satisfy -from its authoritative data or cache to a fixed list of other servers. The -forwarded queries are also known as recursive queries, the same type as a -client would send to a server. There may be one or more servers -forwarded to, and they are queried in turn until the list is exhausted or an -answer is found. A forwarding server is typically used when you do not -wish all the servers at a given site to interact with the rest of the Internet -servers. A typical scenario would involve a number of internal DNS -servers and an Internet firewall. Servers unable to pass packets through -the firewall would forward to the server that can do it, and that server -would query the Internet DNS servers on the internal server's behalf. An -added benefit of using the forwarding feature is that the central machine -develops a much more complete cache of information that all the -workstations can take advantage of. +Instead of interacting with the nameservers for the root and other domains, +a forwarding server always forwards queries it cannot satisfy from its +authoritative data or cache to a fixed list of other servers. The forwarded +queries are also known as recursive queries , the same type as a client +would send to a server. There may be one or more servers forwarded to, and +they are queried in turn until the list is exhausted or an answer is found. +A forwarding server is typically used when you do not wish all the servers +at a given site to interact with the rest of the Internet servers. A typical +scenario would involve a number of internal DNS servers and an Internet +firewall. Servers unable to pass packets through the firewall would forward +to the server that can do it, and that server would query the Internet DNS +servers on the internal server's behalf. An added benefit of using the +forwarding feature is that the central machine develops a much more complete +cache of information that all the workstations can take advantage of. -There is no prohibition against declaring a server to be a forwarder even -though it has master and/or slave zones as well; the effect will still be that -anything in the local server's cache or zones will be answered, and +There is no prohibition against declaring a server to be a forwarder even +though it has master and/or slave zones as well; the effect will still be +that anything in the local server's cache or zones will be answered, and anything else will be forwarded using the forwarders list. -1.4.3.5 Stealth Server + 1.4.3.5 Stealth Server -A stealth server is a server that answers authoritatively for a zone, but is -not listed in that zone's NS records. Stealth servers can be used as a way -to centralize distribution of a zone, without having to edit the zone on a -remote nameserver. Where the master file for a zone resides on a stealth -server in this way, it is often referred to as a "hidden primary" -configuration. Stealth servers can also be a way to keep a local copy of a -zone for rapid access to the zone's records, even if all "official" +A stealth server is a server that answers authoritatively for a zone, but is +not listed in that zone's NS records. Stealth servers can be used as a way +to centralize distribution of a zone, without having to edit the zone on a +remote nameserver. Where the master file for a zone resides on a stealth +server in this way, it is often referred to as a "hidden primary" +configuration. Stealth servers can also be a way to keep a local copy of a +zone for rapid access to the zone's records, even if all "official" nameservers for the zone are inaccessible. + ------------------------------------------------------------------------ + Section 2. BIND Resource Requirements -Section 2. BIND Resource Requirements + 2.1 Hardware requirements -2.1 Hardware requirements +DNS hardware requirements have traditionally been quite modest. For many +installations, servers that have been pensioned off from active duty have +performed admirably as DNS servers. -DNS hardware requirements have traditionally been quite modest. For many installations, -servers that have been pensioned off from active duty have performed admirably as DNS -servers. +The DNSSEC and IPv6 features of BIND 9 may prove to be quite CPU intensive +however, so organizations that make heavy use of these features may wish to +consider larger systems for these applications. BIND 9 is now fully +multithreaded, allowing full utilization of multiprocessor systems for +installations that need it. -The DNSSEC and IPv6 features of BINDv9 may prove to be quite CPU intensive however, -so organizations that make heavy use of these features may wish to consider larger systems -for these applications. BINDv9 is now fully multithreaded, allowing full utilization of -multiprocessor systems for installations that need it. + 2.2 CPU Requirements -2.2 CPU Requirements +CPU requirements for BIND 9 range from i486-class machines for serving of +static zones without caching, to enterprise-class machines if you intend to +process many dynamic updates and DNSSEC signed zones, serving many thousands +of queries per second. -CPU requirements for BINDv9 range from i486-class machines for serving of static zones -without caching, to enterprise-class machines if you intend to process many dynamic -updates and DNSSEC signed zones, serving many thousands of queries per second. + 2.3 Memory Requirements -2.3 Memory Requirements +The memory of the server has to be large enough to fit the cache and zones +loaded off disk. Future releases of BIND 9 will provide methods to limit the +amount of memory used by the cache, at the expense of reducing cache hit +rates and causing more DNS traffic. It is still good practice to have enough +memory to load all zone and cache data into memory--unfortunately, the best +way to determine this for a given installation is to watch the nameserver in +operation. After a few weeks the server process should reach a relatively +stable size where entries are expiring from the cache as fast as they are +being inserted. Ideally, the resource limits should be set higher than this +stable size. -The memory of the server has to be large enough to fit the cache and zones loaded off disk. -Future releases of BINDv9 will provide methods to limit the amount of memory used by the -cache, at the expense of reducing cache hit rates and causing more DNS traffic. It is still -good practice to have enough memory to load all zone and cache data into memory- -unfortunately, the best way to determine this for a given installation is to watch the -nameserver in operation. After a few weeks the server process should reach a relatively -stable size where entries are expiring from the cache as fast as they are being inserted. -Ideally, the resource limits should be set higher than this stable size. + 2.4 Nameserver Intensive Environment Issues -2.4 Nameserver Intensive Environment Issues +For nameserver intensive environments, there are two alternative +configurations that may be used. The first is where clients and any +second-level internal nameservers query a main nameserver, which has enough +memory to build a large cache. This approach minimizes the bandwidth used by +external name lookups. The second alternative is to set up second-level +internal nameservers to make queries independently. In this configuration, +none of the individual machines needs to have as much memory or CPU power as +in the first alternative, but this has the disadvantage of making many more +external queries, as none of the nameservers share their cached data. -For nameserver intensive environments, there are two alternative configurations that may be -used. The first is where clients and any second-level internal nameservers query a main -nameserver, which has enough memory to build a large cache. This approach minimizes the -bandwidth used by external name lookups. The second alternative is to set up second-level -internal nameservers to make queries independently. In this configuration, none of the -individual machines needs to have as much memory or CPU power as in the first alternative, -but this has the disadvantage of making many more external queries, as none of the -nameservers share their cached data. + 2.5 Supported Operating Systems -2.5 Operating Systems Supported by the Internet Software Consortium - -ISC BINDv9 compiles and runs on the following operating systems: +ISC BIND 9 compiles and runs on the following operating systems: IBM AIX 4.3 Compaq Digital/Tru64 UNIX 4.0D @@ -476,334 +482,349 @@ Sun Solaris 2.6, 7, 8 (beta) FreeBSD 3.4-STABLE NetBSD-current with "unproven" pthreads + ------------------------------------------------------------------------ + Section 3. Nameserver Configuration -Section 3. Nameserver Configuration +In this section we provide some suggested configurations along with +guidelines for their use. We also address the topic of reasonable option +setting. -In this section we provide some suggested configurations along with guidelines for their use. We -also address the topic of reasonable option setting. + 3.1 Sample Configurations -3.1 Sample Configuration and Logging + 3.1.1 A Caching-only Nameserver -logging { - channel named_log { - file "logs/named.log"; - print-time yes; - print-category yes; - print-severity yes; - severity info; -}; - channel security_log { - file "logs/security.log" versions 7 ; - print-time yes; -}; - category default { named_log; default_debug; }; - category security { security_log }; -}; - // The two corporate subnets. - // Use real IP numbers - // here in the real world. -acl corpnet { 192.168.4.0/24; 192.168.7.0/24; }; - // The options statement. +The following sample configuration is appropriate for a caching-only name +server for use by clients internal to a corporation. All queries from +outside clients are refused. + +// Two corporate subnets we wish to allow queries from. +acl "corpnets" { 192.168.4.0/24; 192.168.7.0/24; }; options { - directory "/etc/namedb"; // Directory - pid-file "named.pid"; // Put .pid file in named directory. - check-names master fail; // Fail on db errors in master zones. - check-names slave warn; // Warn about db errors - // in slave zones. - check-names response warn; // Warn about invalid responses - use-id-pool yes; // Help prevent spoofing - host-statistics yes; // Keep track of hosts/servers - // we've talked to. - listen-on { 192.168.7.20; }; // Listen on this address. - query-source address 192.168.7.20 port 53 ; - // Source queries from port 53 - // to get past firewall. - allow-transfer { none; }; // Don't allow anyone to - // transfer zones. - allow-query { corpnet; }; // Allow only corpnets to query server. - // Helps prevent DoS, spoofing. - allow-recursion { corpnet; }; // Same, except this is for recursion. + directory "/etc/namedb"; // Working directory + pid-file "named.pid"; // Put pid file in working dir + allow-query { "corpnets "; }; +}; +// Root server hints +zone "." { type hint; file "root.hint"; }; +// Provide a reverse mapping for the loopback address 127.0.0.1 +zone "0.0.127.in-addr.arpa" { + type master; + file "localhost.rev"; + notify no; + }; -include "keys.conf"; // Include a keys.conf with - // TSIG/DNSSEC keys. - // Shouldn't be readable to anyone - // except BIND user. -zone "."{ type hint; file "local/named.root"; }; - // root hints + 3.1.2 An Authoritative-only Nameserver -zone "0.0.127.IN-ADDR.ARPA" { - type master; file "local/localhost.db"; notify no; - // localhost +This sample configuration is for an authoritative-only server that is the +master server for " example.com " and a slave for the subdomain " +eng.example.com ". + +options { + directory "/etc/namedb"; // Working directory + pid-file "named.pid"; // Put pid file in working dir + allow-query { any; }; // This is the default + recursion no; // Do not provide recursive service +}; +// Root server hints +zone "." { type hint; file "root.hint"; }; + +// Provide a reverse mapping for the loopback address 127.0.0.1 + zone "0.0.127.in-addr.arpa" { + type master; + file "localhost.rev"; + notify no; +}; +// We are the master server for example.com +zone "example.com" { + type master; + file "example.com.db"; + // IP addresses of slave servers allowed to transfer example.com + allow-transfer { + 192.168.4.14; + 192.168.5.53; + }; }; -zone "example.com" { // Example zone for "example.com". -type master; // It's a master zone. -file "m/example.com.db"; // The file is here. -allow-query { any; }; // Allow anyone to query. -allow-transfer { corpnet; }; // Only allow corp nets to transfer zone. +// We are a slave server for eng.example.com +zone "eng.example.com" { + type slave; + file "eng.example.com.bk"; + // IP address of eng.example.com master server + masters { 192.168.4.12; }; }; -zone "offsite.example.com" { // Example zone for an off-site corp zone. -type slave; // It's a slave zone. -masters { 192.168.4.12; }; // The master is at this address. -file "s/offsite.example.com.db"; // The file is here. -notify no; // Don't worry about NOTIFYing. -allow-query { any; }; // Allow anyone to query. -}; + 3.2 Load Balancing -3.2 Load Balancing and Round Robin +Primitive load balancing can be achieved in DNS using multiple A records for +one name. -Primitive load balancing can be achieved in DNS using multiple A records for one name. - -For example, if you have three WWW servers with network addresses of 10.0.0.1, 10.0.0.2 -and 10.0.0.3, a set of records like the following means that clients will connect to each -machine one third of the time: +For example, if you have three WWW servers with network addresses of +10.0.0.1, 10.0.0.2 and 10.0.0.3, a set of records such as the following +means that clients will connect to each machine one third of the time: -Name TTL CLASS TYPE Resource Record (RR) Data -www 600 IN A 10.0.0.1 - 600 IN A 10.0.0.2 - 600 IN A 10.0.0.3 + NameTTL CLASS TYPE Resource Record (RR) Data + www 600 IN A 10.0.0.1 + 600 IN A 10.0.0.2 + 600 IN A 10.0.0.3 +When a resolver queries for these records, BIND will rotate them and respond +to the query with the records in a different order. In the example above, +clients will randomly receive records in the order 1, 2, 3; 2, 3, 1; and 3, +1, 2. Most clients will use the first record returned and discard the rest. -When a resolver queries for these records, BIND will rotate them and respond to the query -with the records in a different order. This is known as cyclic or round-robin ordering. In the -example above, the first client will receive the records in the order 1, 2, 3; the second client -will receive them in the order 2, 3, 1; and the third 3, 1, 2. Most clients will use the first -record returned and discard the rest. +For more detail on ordering responses, check the rrset-order substatement in +the options statement under RRset Ordering. This substatement is not +supported in BIND 9, and only the ordering scheme described above is +available. -For more detail on ordering responses, check the rrset-order substatement in the options -statement in Section 5.2.12.12, "RRset Ordering", on page 52. + 3.3 Notify -3.3 Notify +DNS Notify is a mechanism that allows master nameservers to notify their +slave servers of changes to a zone's data. In response to a NOTIFY from a +master server, the slave will check to see that its version of the zone is +the current version and, if not, initiate a transfer. -DNS Notify is a mechanism that allows master nameservers to notify their slave servers of -changes to a zone's data and that a query should be initiated to discover the new data. +DNS Notify is fully documented in RFC 1996. See also the description of the +zone option also-notify under Zone Transfers . More information about notify +can be found under Boolean Options . -DNS Notify is fully documented in RFC 1996. See also the description of the zone option -also-notify in Section 5.2.12.7, "Zone Transfers", on page 46. More information about -notify can be found in Section 5.2.12.1, "Boolean Options", on page 40. + 3.4 Nameserver Operations -3.4 Nameserver Operations + 3.4.1 Tools for Use With the Nameserver Daemon -3.4.1 Tools for Use With the Nameserver Daemon +There are several indispensable diagnostic, administrative and monitoring +tools available to the system administrator for controlling and debugging +the nameserver daemon. We describe several in this section -There are several indispensable diagnostic, administrative and monitoring tools -available to the system administrator for controlling and debugging the nameserver -daemon. We describe several in this section - -3.4.1.1 Diagnostic Tools + 3.4.1.1 Diagnostic Tools dig -The domain information groper (dig) is a command line tool that can be -used to gather information from the Domain Name System servers. Dig -has two modes: simple interactive mode for a single query, and batch -mode which executes a query for each in a list of several query lines. All -query options are accessible from the command line. +The domain information groper ( dig ) is a command line tool that can be +used to gather information from the Domain Name System servers. Dig has two +modes: simple interactive mode for a single query, and batch mode which +executes a query for each in a list of several query lines. All query +options are accessible from the command line. Usage dig [@server] domain [] [] -[+] [-] [%comment] + [+] [-] [%comment] The usual simple use of dig will take the form dig @server domain query-type query-class -For more information and a list of available commands and options, see -the dig man page. +For more information and a list of available commands and options, see the +dig man page. host -The host utility provides a simple DNS lookup using a command-line -interface for looking up Internet hostnames. By default, the utility -converts between host names and Internet addresses, but its functionality -can be extended with the use of options. +The host utility provides a simple DNS lookup using a command-line interface +for looking up Internet hostnames. By default, the utility converts between +host names and Internet addresses, but its functionality can be extended +with the use of options. Usage -host [-l] [-v] [-w] [-r] [-d] [-t querytype] [-a] host [server] +host [-aCdlrTwv] [-c class] [-N ndots] [-t type] + [-W timeout] [-R retries] hostname [server] nslookup -nslookup is a program used to query Internet domain nameservers. -nslookup has two modes: interactive and non-interactive. Interactive -mode allows the user to query nameservers for information about various -hosts and domains or to print a list of hosts in a domain. Non-interactive -mode is used to print just the name and requested information for a host or -domain. +nslookup is a program used to query Internet domain nameservers. nslookup +has two modes: interactive and non-interactive. Interactive mode allows the +user to query nameservers for information about various hosts and domains or +to print a list of hosts in a domain. Non-interactive mode is used to print +just the name and requested information for a host or domain. Usage nslookup [-option ...] [host-to-find | -[server]] -Interactive mode is entered when no arguments are given (the default -nameserver will be used) or when the first argument is a hyphen (-) and +Interactive mode is entered when no arguments are given (the default +nameserver will be used) or when the first argument is a hyphen (`-') and the second argument is the host name or Internet address of a nameserver. -Non-interactive mode is used when the name or Internet address of the -host to be looked up is given as the first argument. The optional second -argument specifies the host name or address of a nameserver. +Non-interactive mode is used when the name or Internet address of the host +to be looked up is given as the first argument. The optional second argument +specifies the host name or address of a nameserver. -The options listed under the "set" command (see the nslookup man page -for details) can be specified in the .nslookuprc file in the user's home -directory if they are listed one per line. Options can also be specified on -the command line if they precede the arguments and are prefixed with a -hyphen. For example, to change the default query type to host -information, and the initial time-out to 10 seconds, type: +The options listed under the "set" command (see the nslookup man page for +details) can be specified in the .nslookuprc file in the user's home +directory if they are listed one per line. Options can also be specified on +the command line if they precede the arguments and are prefixed with a +hyphen. For example, to change the default query type to host information, +and the initial time-out to 10 seconds, type: nslookup -query=hinfo -timeout=10 -For more information and a list of available commands and options, see -the nslookup man page. +For more information and a list of available commands and options, see the +nslookup man page. -3.4.1.2 Administrative Tools +Due to its arcane user interface and frequently inconsistent behavior, we do +not recommend the use of nslookup , and it is not installed by default when +installing BIND 9. Use dig instead. + + 3.4.1.2 Administrative Tools Administrative tools play an integral part in the management of a server. rndc -The remote name daemon control (rndc) program is a program that -allows the system administrator to control the operation of a nameserver. -If you run rndc without any options it will display a usage message. +The remote name daemon control ( rndc ) program is a program that allows the +system administrator to control the operation of a nameserver. If you run +rndc without any options it will display a usage message. Usage: rndc [-p port] [-m] server command [command ...] -For more information and a list of available commands and options, see -the rndc man page. +For more information and a list of available commands and options, see the +rndc man page. + ------------------------------------------------------------------------ +Section 4. Advanced Concepts -Section 4. Advanced Concepts +4.1 Dynamic Update -4.1 Dynamic Update +Dynamic update is the term used for the ability under certain specified +conditions to add, modify or delete records or RRsets in the master zone +files. Dynamic update is fully described in RFC 2136. -Dynamic update is the term used for the ability under certain specified conditions to add, -modify or delete records or RRsets in the master zone files. Dynamic update is fully -described in RFC 2136. +Dynamic update is enabled on a zone-by-zone basis, by including an +allow-update or update-policy clause in the zone statement. -Dynamic update is enabled on a zone-by-zone basis, by including an allow-update or -update-policy clause in the zone statement. +Updating of secure zones (zones using DNSSEC) is modelled after the +simple-secure-update proposal, a work in progress in the DNS Extensions +working group of the IETF. (See +http://www.ietf.org/html.charters/dnsext-charter.html for information about +the DNS Extensions working group.) SIG and NXT records affected by updates +are automatically regenerated by the server using an online zone key. Update +authorization is based on transaction signatures and an explicit server +policy. -Updating of secure zones (zones using DNSSEC) is modelled after the simple-secure-update -proposal, a work in progress in the DNS Extensions working group of the IETF. (See -http://www.ietf.org/html.charters/dnsext-charter.html for information about the DNS Extensions -working group.) SIG and NXT records affected by updates are automatically regenerated by -the server using an online zone key. Update authorization is based on transaction signatures -and an explicit server policy. +The zone files of dynamic zones must not be edited by hand. The zone file on +disk at any given time may not contain the latest changes performed by +dynamic update. The zone file is written to disk only periodically, and +changes that have occurred since the zone file was last written to disk are +stored only in the zone's journal ( .jnl ) file. BIND 9 currently does not +update the zone file when it exits as BIND 8 does, so editing the zone file +manually is unsafe even when the server has been shut down. -The zone files of dynamic zones must not be edited by hand. The zone file on disk at any -given time may not contain the latest changes performed by dynamic update. The zone file is -written to disk only periodically, and changes that have occurred since the zone file was last -written to disk are stored only in the zone's journal (.jnl) file. BINDv9 currently does not -update the zone file when it exits like BIND 8 does, so editing the zone file manually is -unsafe even when the server has been shut down. +4.2 Incremental Zone Transfers (IXFR) -4.2 Incremental Zone Transfers (IXFR) +The incremental zone transfer (IXFR) protocol is a way for slave servers to +transfer only changed data, instead of having to transfer the entire zone. +The IXFR protocol is documented in RFC 1995. See the list of proposed +standards in Appendix C . -The incremental zone transfer (IXFR) protocol is a way for slave servers to transfer only -changed data, instead of having to transfer the entire zone. The IXFR protocol is -documented in RFC 1995. See the list of proposed standards in Appendix C, Section C.1.2, -"Proposed Standards", page 83. +When acting as a master, BIND 9 supports IXFR for those zones where the +necessary change history information is available. These include master +zones maintained by dynamic update and slave zones whose data was obtained +by IXFR, but not manually maintained master zones nor slave zones obtained +by performing a full zone transfer (AXFR). -When acting as a master, BINDv9 supports IXFR for those zones where the necessary -change history information is available. These include master zones maintained by dynamic -update and slave zones whose data was obtained by IXFR, but not manually maintained -master zones nor slave zones obtained by performing a full zone transfer (AXFR). +When acting as a slave, BIND 9 will attempt to use IXFR unless it is +explicitly disabled. For more information about disabling IXFR, see the +description of the request-ixfr clause of the server statement. -When acting as a slave, BINDv9 will attempt to use IXFR unless it is explicitly disabled. For -more information about disabling IXFR, see the description of the request-ixfr clause of -the server statement. +4.3 Split DNS -4.3 Split DNS +Setting up different views, or visibility, of DNS space to internal and +external resolvers is usually referred to as a Split DNS setup. There are +several reasons an organization would want to set up its DNS this way. -Setting up different views, or visibility, of DNS space to internal, as opposed to external, -resolvers is usually referred to as a Split DNS or Split Brain DNS setup. There are several -reasons an organization would want to set up its DNS this way. +One common reason for setting up a DNS system this way is to hide "internal" +DNS information from "external" clients on the Internet. There is some +debate as to whether or not this is actually useful. Internal DNS +information leaks out in many ways (via email headers, for example) and most +savvy "attackers" can find the information they need using other means. -One common reason for setting up a DNS system this way is to hide "internal" DNS -information from "external" clients on the Internet. There is some debate as to whether or -not this is actually useful. Internal DNS information leaks out in many ways (via email -headers, for example) and most savvy "attackers" can find the information they need using -other means. - -Another common reason for setting up a Split DNS system is to allow internal networks that -are behind filters or RFC 1918 space (reserved IP space, as documented in RFC 1918) to -resolve DNS on the Internet. Split DNS can also be used to allow mail from outside back in -to the internal network. +Another common reason for setting up a Split DNS system is to allow internal +networks that are behind filters or in RFC 1918 space (reserved IP space, as +documented in RFC 1918) to resolve DNS on the Internet. Split DNS can also +be used to allow mail from outside back in to the internal network. Here is an example of a split DNS setup: -Let's say a company named Example, Inc. (example.com) has several corporate sites that -have an internal network with reserved Internet Protocol (IP) space and an external -demilitarized zone (DMZ), or "outside" section of a network, that is available to the public. +Let's say a company named Example, Inc. (example.com) has several corporate +sites that have an internal network with reserved Internet Protocol (IP) +space and an external demilitarized zone (DMZ), or "outside" section of a +network, that is available to the public. -Example, Inc. wants its internal clients to be able to resolve external hostnames and to -exchange mail with people on the outside. The company also wants its internal resolvers to -have access to certain internal-only zones that are not available at all outside of the internal -network. +Example, Inc. wants its internal clients to be able to resolve external +hostnames and to exchange mail with people on the outside. The company also +wants its internal resolvers to have access to certain internal-only zones +that are not available at all outside of the internal network. -In order to accomplish this, the company will set up two sets of nameservers. One set will be -on the inside network (in the reserved IP space) and the other set will be on bastion hosts, -which are "proxy" hosts that can talk to both sides of its network, in the DMZ. +In order to accomplish this, the company will set up two sets of +nameservers. One set will be on the inside network (in the reserved IP +space) and the other set will be on bastion hosts, which are "proxy" hosts +that can talk to both sides of its network, in the DMZ. -The internal servers will be configured to forward all queries, except queries for -site1.example, site2.example, site1.example.com, and site2.example.com, to the servers in the -DMZ. These internal servers will have complete sets of information for site1.example.com, -site2.example.com, site1.internal, and site2.internal. +The internal servers will be configured to forward all queries, except +queries for site1.internal , site2.internal , site1.example.com , and +site2.example.com , to the servers in the DMZ. These internal servers will +have complete sets of information for site1.example.com , site2.example.com +, site1.internal , and site2.internal . -To protect the site1.internal and site2.internal domains, the internal nameservers must be -configured to disallow all queries to these domains from any external hosts, including the -bastion hosts. +To protect the site1.interna l and site2.internal domains, the internal +nameservers must be configured to disallow all queries to these domains from +any external hosts, including the bastion hosts. -The external servers, which are on the bastion hosts, will be configured to serve the "public" -version of the site1 and site2.example.com zones. This could include things such as the host -records for public servers (www.example.com and ftp.example.com), and mail exchange (MX) -records (a.mx.example.com and b.mx.example.com). +The external servers, which are on the bastion hosts, will be configured to +serve the "public" version of the site1 and site2.example.com zones. This +could include things such as the host records for public servers ( +www.example.com and ftp.example.com ), and mail exchange (MX) records ( +a.mx.example.com and b.mx.example.com ). -In addition, the public site1 and site2.example.com zones should have special MX records that -contain wildcard (`*') records pointing to the bastion hosts. This is needed because external -mail servers do not have any other way of looking up how to deliver mail to those internal -hosts. With the wildcard records, the mail will be delivered to the bastion host, which can -then forward it on to internal hosts. +In addition, the public site1 and site2.example.com zones should have +special MX records that contain wildcard (`*') records pointing to the +bastion hosts. This is needed because external mail servers do not have any +other way of looking up how to deliver mail to those internal hosts. With +the wildcard records, the mail will be delivered to the bastion host, which +can then forward it on to internal hosts. Here's an example of a wildcard MX record: * IN MX 10 external1.example.com. -Now that they accept mail on behalf of anything in the internal network, the bastion hosts -will need to know how to deliver mail to internal hosts. In order for this to work properly, the -resolvers on the bastion hosts will need to be configured to point to the internal nameservers -for DNS resolution. +Now that they accept mail on behalf of anything in the internal network, the +bastion hosts will need to know how to deliver mail to internal hosts. In +order for this to work properly, the resolvers on the bastion hosts will +need to be configured to point to the internal nameservers for DNS +resolution. -Queries for internal hostnames will be answered by the internal servers, and queries for -external hostnames will be forwarded back out to the DNS servers on the bastion hosts. +Queries for internal hostnames will be answered by the internal servers, and +queries for external hostnames will be forwarded back out to the DNS servers +on the bastion hosts. -In order for all this to work properly, internal clients will need to be configured to query only -the internal nameservers for DNS queries. This could also be enforced via selective filtering -on the network. +In order for all this to work properly, internal clients will need to be +configured to query only the internal nameservers for DNS queries. This +could also be enforced via selective filtering on the network. -If everything has been set properly, Example, Inc.'s internal clients will now be able to: +If everything has been set properly, Example, Inc. 's internal clients will +now be able to: -o Look up any hostnames in the site1 and site2.example.com zones. -o Look up any hostnames in the site1.internal and site2.internal domains. -o Look up any hostnames on the Internet. -o Exchange mail with internal AND external people. + * Look up any hostnames in the site1 and site2.example.com zones. + * Look up any hostnames in the site1.internal and site2.internal domains. + * Look up any hostnames on the Internet. + * Exchange mail with internal AND external people. Hosts on the Internet will be able to: -o Look up any hostnames in the site1 and site2.example.com zones. -o Exchange mail with anyone in the site1 and site2.example.com zones. + * Look up any hostnames in the site1 and site2.example.com zones. + * Exchange mail with anyone in the site1 and site2.example.com zones. -Here is an example configuration for the setup we just described above. Note that this is only -configuration information; for information on how to configure your zone files, see Section -3.1, "Sample Configuration and Logging", page 9. +Here is an example configuration for the setup we just described above. Note +that this is only configuration information; for information on how to +configure your zone files, see the Sample Configurations . Internal DNS server config: @@ -815,12 +836,12 @@ options { forward only; forwarders { bastion-ips-go-here; }; // forward to external servers allow-transfer { none; }; // sample allow-transfer (no one) - allow-query { internals; externals; }; // restrict query access + allow-query { internal; externals; }; // restrict query access allow-recursion { internals; }; // restrict recursion ... ... }; - + zone "site1.example.com" { // sample slave zone type master; file "m/site1.example.com"; @@ -828,7 +849,7 @@ zone "site1.example.com" { // sample slave zone // resolution (do not forward) allow-query { internals; externals; }; allow-transfer { internals; }; -}; + }; zone "site2.example.com" { type slave; @@ -859,18 +880,19 @@ zone "site2.internal" { External (bastion host) DNS server config: acl internals { 172.16.72.0/24; 192.168.1.0/24; }; -acl externals { bastion-ips-go-here; }; +acl externals { +bastion-ips-go-here; }; options { ... ... - allow-transfer { none;}; // sample allow-transfer (no one) - allow-query { internals; externals; }; // restrict query access - allow-recursion { internals; externals; }; // restrict recursion + allow-transfer { none; }; // sample allow-transfer (no one) + allow-query { internals; externals; }; // restrict query access + allow-recursion { internals; externals; }; // restrict recursion ... ... }; -zone "site1.example.com" { // sample slave zone +zone "site1.example.com" { // sample slave zone type master; file "m/site1.foo.com"; allow-query { any; }; @@ -892,409 +914,414 @@ nameserver 172.16.72.2 nameserver 172.16.72.3 nameserver 172.16.72.4 -4.4 TSIG +4.4 TSIG -This is a short guide to setting up Transaction SIGnatures (TSIG) based transaction security -in BIND. It describes changes to the configuration file as well as what changes are required -for different features, including the process of creating transaction keys and using -transaction signatures with BIND. +This is a short guide to setting up Transaction SIGnatures (TSIG) based +transaction security in BIND. It describes changes to the configuration file +as well as what changes are required for different features, including the +process of creating transaction keys and using transaction signatures with +BIND. -BIND primarily supports TSIG for server to server communication. This includes zone -transfer, notify, and recursive query messages. The resolver bundled with BIND 8.2 has -limited support for TSIG, but it is doubtful that support will be integrated into any client -applications. +BIND primarily supports TSIG for server to server communication. This +includes zone transfer, notify, and recursive query messages. Resolvers +based on newer versions of BIND 8 have limited support for TSIG. -TSIG might be most useful for dynamic update. A primary server for a dynamic zone should -use access control to control updates, but IP-based access control is insufficient. Key-based -access control is far superior. See RFC 2845 in "Proposed Standards" on page 83 of the -Appendix. The nsupdate program that is shipped with BIND 8 supports TSIG via the "-k" -command line option. +TSIG might be most useful for dynamic update. A primary server for a dynamic +zone should use access control to control updates, but IP-based access +control is insufficient. Key-based access control is far superior. See RFC +2845 in the Proposed Standards section of the Appendix. The nsupdate program +that is shipped with BIND 8 supports TSIG via the " -k " command line +option. -4.4.1 Generate Shared Keys for Each Pair of Hosts +4.4.1 Generate Shared Keys for Each Pair of Hosts -A shared secret is generated to be shared between host1 and host2. The key name is -chosen to be "host1-host2.", which is arbitrary. The key name must be the same on -both hosts. +A shared secret is generated to be shared between host1 and host2 . An +arbitrary key name is chosen: "host1-host2.". The key name must be the same +on both hosts. -4.4.1.1 Automatic Generation +4.4.1.1 Automatic Generation -The following command will generate a 128 bit (16 byte) HMAC-MD5 -key as described above. Longer keys are better, but shorter keys are easier -to read. Note that the maximum key length is 512 bits; keys longer than -that will be digested with MD5 to produce a 128 bit key. +The following command will generate a 128 bit (16 byte) HMAC-MD5 key as +described above. Longer keys are better, but shorter keys are easier to +read. Note that the maximum key length is 512 bits; keys longer than that +will be digested with MD5 to produce a 128 bit key. -bin/dnssec/dnssec-keygen -a hmac-md5 -b 128 -n HOST host1-host2. +dnssec-keygen -a hmac-md5 -b 128 -n HOST host1-host2. -The key is in the file "Khost1-host2.+157+00000.private". Nothing -actually uses this file, but the base-64 encoded string following "Key:" -can be extracted: +The key is in the file Khost1-host2.+157+00000.private . Nothing directly +uses this file, but the base-64 encoded string following " Key :" can be +extracted from the file and used as a shared secret: - La/E5CjG9O+os1jq0a2jdA== +Key: La/E5CjG9O+os1jq0a2jdA== -This string represents a shared secret. +The string " La/E5CjG9O+os1jq0a2jdA== " can be used as the shared secret. -4.4.1.2 Manual Generation +4.4.1.2 Manual Generation -The shared secret is simply a random sequence of bits, encoded in base- -64. Most ASCII strings are valid base-64 strings (assuming the length is a -multiple of 4 and only valid characters are used), so the shared secret can +The shared secret is simply a random sequence of bits, encoded in base-64. +Most ASCII strings are valid base-64 strings (assuming the length is a +multiple of 4 and only valid characters are used), so the shared secret can be manually generated. -Also, a known string can be run through mmencode or a similar program to +Also, a known string can be run through mmencode or a similar program to generate base-64 encoded data. -4.4.2 Copying the Shared Secret to Both Machines +4.4.2 Copying the Shared Secret to Both Machines -This is beyond the scope of DNS. A secure transport mechanism should be used. -This could be secure FTP, ssh, telephone, etc. +This is beyond the scope of DNS. A secure transport mechanism should be +used. This could be secure FTP, ssh, telephone, etc. -4.4.3 Informing the Servers of the Key's Existence +4.4.3 Informing the Servers of the Key's Existence -Imagine host1 and host 2 are both servers. The following is added to each server's -named.conf file: +Imagine host1 and host 2 are both servers. The following is added to each +server's named.conf file: key host1-host2. { algorithm hmac-md5; secret "La/E5CjG9O+os1jq0a2jdA=="; }; -The algorithm, hmac-md5, is the only one supported by BIND. The secret is the one -generated above. Since this is a secret, it is recommended that either named.conf be -non-world readable, or the key directive be added to a non-world readable file that is -included by named.conf. +The algorithm, hmac-md5, is the only one supported by BIND. The secret is +the one generated above. Since this is a secret, it is recommended that +either named.conf be non-world readable, or the key directive be added to a +non-world readable file that is included by named.conf . -At this point, the key is recognized. This means that if the server receives a message -signed by this key, it can verify the signature. If the signature succeeds, the response -is signed by the same key. +At this point, the key is recognized. This means that if the server receives +a message signed by this key, it can verify the signature. If the signature +succeeds, the response is signed by the same key. -4.4.4 Instructing the Server to Use the Key +4.4.4 Instructing the Server to Use the Key -Since keys are shared between two hosts only, the server must be told when keys are -to be used. The following is added to the named.conf file for host1, if the IP address -of host2 is 10.1.2.3: +Since keys are shared between two hosts only, the server must be told when +keys are to be used. The following is added to the named.conf file for host1 +, if the IP address of host2 is 10.1.2.3: server 10.1.2.3 { keys { host1-host2. ;}; }; -Multiple keys may be present, but only the first is used. This directive does not -contain any secrets, so it may be in a world-readable file. +Multiple keys may be present, but only the first is used. This directive +does not contain any secrets, so it may be in a world-readable file. -If host1 sends a message that is a response to that address, the message will be -signed with the specified key. host1 will expect any responses to signed messages to -be signed with the same key. +If host1 sends a message that is a response to that address, the message +will be signed with the specified key. host1 will expect any responses to +signed messages to be signed with the same key. -A similar statement must be present in host2's configuration file (with host1's -address) for host2 to sign non-response messages to host1. +A similar statement must be present in host2 's configuration file (with +host1 's address) for host2 to sign non-response messages to host1 . -4.4.5 TSIG Key Based Access Control +4.4.5 TSIG Key Based Access Control BIND allows IP addresses and ranges to be specified in ACL definitions and -allow-{ query | transfer | update } directives. This has been extended to +allow-{ query | transfer | update } directives. This has been extended to allow TSIG keys also. The above key would be denoted key host1-host2. An example of an allow-update directive would be: allow-update { key host1-host2. ;}; -This allows dynamic updates to succeed only if the request was signed by a key -named "host1-host2.". +This allows dynamic updates to succeed only if the request was signed by a +key named " host1-host2. ". -4.4.6 Errors +The more powerful update-policy statement is described Dynamic Update +Policies . -The processing of TSIG signed messages can result in several errors. If a signed -message is sent to a non-TSIG aware server, a FORMERR will be returned, since -the server will not understand the record. This is a result of misconfiguration, since -the server must be explicitly configured to send a TSIG signed message to a specific -server. +4.4.6 Errors -If a TSIG aware server receives a message signed by an unknown key, the response -will be unsigned with the TSIG extended error code set to BADKEY. If a TSIG -aware server receives a message with a signature that does not validate, the response -will be unsigned with the TSIG extended error code set to BADSIG. If a TSIG -aware server receives a message with a time outside of the allowed range, the -response will be signed with the TSIG extended error code set to BADTIME, and -the time values will be adjusted so that the response can be successfully verified. In -any of these cases, the message's rcode is set to NOTAUTH. +The processing of TSIG signed messages can result in several errors. If a +signed message is sent to a non-TSIG aware server, a FORMERR will be +returned, since the server will not understand the record. This is a result +of misconfiguration, since the server must be explicitly configured to send +a TSIG signed message to a specific server. -4.5 TKEY +If a TSIG aware server receives a message signed by an unknown key, the +response will be unsigned with the TSIG extended error code set to BADKEY. +If a TSIG aware server receives a message with a signature that does not +validate, the response will be unsigned with the TSIG extended error code +set to BADSIG. If a TSIG aware server receives a message with a time outside +of the allowed range, the response will be signed with the TSIG extended +error code set to BADTIME, and the time values will be adjusted so that the +response can be successfully verified. In any of these cases, the message's +rcode is set to NOTAUTH. -TKEY is a mechanism for automatically generating a shared secret between two hosts. There -are several "modes" of TKEY that specify how the key is generated or assigned. BIND -implements only one of these modes, the Diffie-Hellman key exchange. Both hosts are -required to have a Diffie-Hellman KEY record (although this record is not required to be -present in a zone). The TKEY process must use signed messages, signed either by TSIG or -SIG(0). The result of TKEY is a shared secret that can be used to sign messages with TSIG. -TKEY can also be used to delete shared secrets that it had previously generated. +4.5 TKEY -The TKEY process is initiated by a client or server by sending a signed TKEY query (including -any appropriate KEYs) to a TKEY-aware server. The server response, if it indicates success, -will contain a TKEY record and any appropriate keys. After this exchange, both participants -have enough information to determine the shared secret; the exact process depends on the -TKEY mode. When using the Diffie-Hellman TKEY mode, Diffie-Hellman keys are +TKEY is a mechanism for automatically generating a shared secret between two +hosts. There are several "modes" of TKEY that specify how the key is +generated or assigned. BIND implements only one of these modes, the +Diffie-Hellman key exchange. Both hosts are required to have a +Diffie-Hellman KEY record (although this record is not required to be +present in a zone). The TKEY process must use signed messages, signed either +by TSIG or SIG(0). The result of TKEY is a shared secret that can be used to +sign messages with TSIG. TKEY can also be used to delete shared secrets that +it had previously generated. + +The TKEY process is initiated by a client or server by sending a signed TKEY +query (including any appropriate KEYs) to a TKEY-aware server. The server +response, if it indicates success, will contain a TKEY record and any +appropriate keys. After this exchange, both participants have enough +information to determine the shared secret; the exact process depends on the +TKEY mode. When using the Diffie-Hellman TKEY mode, Diffie-Hellman keys are exchanged, and the shared secret is derived by both participants. -4.6 DNSSEC +4.6 SIG(0) -Cryptographic authentication of DNS information is possible through the DNS Security -(DNSSEC) extension, defined in RFC 2535. This section describes the creation and use of -DNSSEC signed zones. +BIND 9 partially supports DNSSEC SIG(0) transaction signatures as specified +in RFC 2535. SIG(0) uses public/private keys to authenticate messages. +Access control is performed in the same manner as TSIG keys; privileges can +be granted or denied based on the key name. -In order to set up a DNSSEC secure zone, there are a series of steps which must be followed. -BINDv9 ships with several tools that are used in this process, which are explained in more -detail below. In all cases, the "-h" option prints a full list of parameters. +When a SIG(0) signed message is received, it will only be verified if the +key is known and trusted by the server; the server will not attempt to +locate and/or validate the key. -There must also be communication with the administrators of the parent and/or child zone to -transmit keys and signatures. A zone's security status must be indicated by the parent zone -for a DNSSEC capable resolver to trust its data. +BIND 9 does not ship with any tools that generate SIG(0) signed messages. -For other servers to trust data in this zone, they must either be statically configured with this -zone's zone key or the zone key of another zone above this one in the DNS tree. +4.7 DNSSEC -4.6.1 Generating Keys +Cryptographic authentication of DNS information is possible through the DNS +Security ( DNSSEC ) extensions, defined in RFC 2535. This section describes +the creation and use of DNSSEC signed zones. + +In order to set up a DNSSEC secure zone, there are a series of steps which +must be followed. BIND 9 ships with several tools that are used in this +process, which are explained in more detail below. In all cases, the " -h " +option prints a full list of parameters. + +There must also be communication with the administrators of the parent +and/or child zone to transmit keys and signatures. A zone's security status +must be indicated by the parent zone for a DNSSEC capable resolver to trust +its data. + +For other servers to trust data in this zone, they must either be statically +configured with this zone's zone key or the zone key of another zone above +this one in the DNS tree. + +4.7.1 Generating Keys The dnssec-keygen program is used to generate keys. -A secure zone must contain one or more zone keys. The zone keys will sign all other records -in the zone, as well as the zone keys of any secure delegated zones. Zone keys must have the -same name as the zone, a name type of ZONE, and must be usable for authentication. It is -recommended that zone keys be mandatory to implement a cryptographic algorithm; -currently the only key mandatory to implement an algorithm is DSA. +A secure zone must contain one or more zone keys. The zone keys will sign +all other records in the zone, as well as the zone keys of any secure +delegated zones. Zone keys must have the same name as the zone, a name type +of ZONE , and must be usable for authentication. It is recommended that zone +keys be mandatory to implement a cryptographic algorithm; currently the only +key mandatory to implement an algorithm is DSA. -The following command will generate a 768 bit DSA key for the child.example zone: +The following command will generate a 768 bit DSA key for the child.example +zone: dnssec-keygen -a DSA -b 768 -n ZONE child.example. -Two output files will be produced: Kchild.example.+003+12345.key and -Kchild.example.+003+12345.private (where 12345 is an example of a key identifier). The key -file names contain the key name (child.example), algorithm (3 is DSA, 1 is RSA, etc.), and the -key identifier (12345 in this case). The private key (in the .private file) is used to generate -signatures, and the public key (in the .key file) is used for signature verification. +Two output files will be produced: Kchild.example.+003+12345.key and +Kchild.example.+003+12345.private (where 12345 is an example of a key +identifier). The key file names contain the key name ( child.example. ), +algorithm (3 is DSA, 1 is RSA, etc.), and the key identifier (12345 in this +case). The private key (in the .private file) is used to generate +signatures, and the public key (in the .key file) is used for signature +verification. -To generate another key with the same properties, repeat the above command. +To generate another key with the same properties (but with a different key +identifier), repeat the above command. -The public keys should be inserted into the zone file with $INCLUDE statements. +The public keys should be inserted into the zone file with $INCLUDE +statements, including the .key files. -4.6.2 Creating a Keyset +4.7.2 Creating a Keyset -The dnssec-makekeyset program is used to create a key set from one or more keys. +The dnssec-makekeyset program is used to create a key set from one or more +keys. -Once the zone keys have been generated, a key set must be built for transmission to the -administrator of the parent zone, so that the parent zone can sign the keys with its own zone -key and correctly indicate the security status of this zone. When building a key set, the list -of keys to be included and the TTL of the set must be specified, and the desired signature -validity period of the parent's signature may also be specified. +Once the zone keys have been generated, a key set must be built for +transmission to the administrator of the parent zone, so that the parent +zone can sign the keys with its own zone key and correctly indicate the +security status of this zone. When building a key set, the list of keys to +be included and the TTL of the set must be specified, and the desired +signature validity period of the parent's signature may also be specified. -The list of keys to be inserted into the key set may also included non-zone keys present at the -apex. dnssec-makekeyset may also be used at non-apex names. +The list of keys to be inserted into the key set may also included non-zone +keys present at the apex. dnssec-makekeyset may also be used at non-apex +names. -The following command generates a key set containing the above key and another key -similarly generated, with a TTL of 3600 and a signature validity period of 10 days starting -from now. +The following command generates a key set containing the above key and +another key similarly generated, with a TTL of 3600 and a signature validity +period of 10 days starting from now. -dnssec-makekeyset -t 3600 -s now -e now+864000 Kchild.example.+003+12345 +dnssec-makekeyset -t 3600 -s now -e now+864000 Kchild.example.+003+12345 Kchild.example.+003+23456 -One output file is produced: child.example.keyset. This file should be transmitted to the parent -to be signed. It includes the keys, as well as signatures over the key set generated by the -zone keys themselves, which are used to prove ownership of the private keys and encode the -desired validity period. +One output file is produced: child.example.keyset . This file should be +transmitted to the parent to be signed. It includes the keys, as well as +signatures over the key set generated by the zone keys themselves, which are +used to prove ownership of the private keys and encode the desired validity +period. -4.6.3 Signing the Child's Keyset +4.7.3 Signing the Child's Keyset The dnssec-signkey program is used to sign one child's keyset. -If the child.example zone has any delegations which are secure, for example, -grand.child.example, the child.example administrator should receive keyset files for each secure -subzone. These keys must be signed by this zone's zone keys. +If the child.example zone has any delegations which are secure, for example, +grand.child.example , the child.example administrator should receive keyset +files for each secure subzone. These keys must be signed by this zone's zone +keys. The following command signs the child's key set with the zone keys: -dnssec-signkey grand.child.example.keyset Kchild.example.+003+12345 +dnssec-signkey grand.child.example.keyset Kchild.example.+003+12345 Kchild.example.+003+23456 -One output file is produced: grand.child.example.signedkey. This file should be both -transmitted back to the child and retained. It includes all keys (the child's keys) from the -keyset file and signatures generated by this zone's zone keys. +One output file is produced: grand.child.example.signedkey . This file +should be both transmitted back to the child and retained. It includes all +keys (the child's keys) from the keyset file and signatures generated by +this zone's zone keys. -4.6.4 Signing the Zone +4.7.4 Signing the Zone The dnssec-signzone program is used to sign a zone. -Any signedkey files corresponding to secure subzones should be present, as well as a -signedkey file for this zone generated by the parent (if there is one). The zone signer will -generate NXT and SIG records for the zone, as well as incorporate the zone key signature -from the parent and indicate the security status at all delegation points. +Any signedkey files corresponding to secure subzones should be present, as +well as a signedkey file for this zone generated by the parent (if there is +one). The zone signer will generate NXT and SIG records for the zone, as +well as incorporate the zone key signature from the parent and indicate the +security status at all delegation points. -The following command signs the zone, assuming it is in a file called zone.child.example. By -default, all zone keys which have an available private key are used to generate signatures. +The following command signs the zone, assuming it is in a file called +zone.child.example . By default, all zone keys which have an available +private key are used to generate signatures. dnssec-signzone -o child.example zone.child.example -One output file is produced: zone.child.example.signed. This file should be referenced by -named.conf as the input file for the zone. +One output file is produced: zone.child.example.signed . This file should be +referenced by named.conf as the input file for the zone. -4.6.5 Configuring Servers +4.7.5 Configuring Servers -Unlike in BIND 8, data is not verified on load in BINDv9, so zone keys for authoritative -zones do not need to be specified in the configuration file. +Unlike in BIND 8, data is not verified on load in BIND 9, so zone keys for +authoritative zones do not need to be specified in the configuration file. -The public key for any security root must be present in the configuration file's -trusted-keys statement, as described later in this document. +The public key for any security root must be present in the configuration +file's +trusted-keys statement, as described later in this document. -4.7 IPv6 +4.8 IPv6 Support in BIND 9 -4.7.1 IPv6 addresses (A6) +BIND 9 fully supports all currently defined forms of IPv6 name to address +and address to name lookups. It will also use IPv6 addresses to make queries +when running on an IPv6 capable system. -IPv6 addresses are 128-bit identifiers for interfaces and sets of interfaces which -were introduced in the DNS to facilitate scalable Internet routing. There are three -types of addresses: Unicast, an identifier for a single interface; Anycast, an identifier -for a set of interfaces; and Multicast, an identifier for a set of interfaces. Here we -describe the global Unicast address scheme. For more information, see RFC 2374. +For forward lookups, BIND 9 supports both A6 and AAAA records. The of AAAA +records is deprecated, but it is still useful for hosts to have both AAAA +and A6 records to maintain backward compatibility with installations where +AAAA records are still used. In fact, the stub resolvers currently shipped +with most operating system support only AAAA lookups, because following A6 +chains is much harder than doing A or AAAA lookups. -The aggregatable global Unicast address format is as follows: +For IPv6 reverse lookups, BIND 9 supports the new "bitstring" format used in +the ip6.arpa domain, as well as the older, deprecated "nibble" format used +in the ip6.int domain. +BIND 9 includes a new lightweight resolver library and resolver daemon which +new applications may choose to use to avoid the complexities of A6 chain +following and bitstring labels. See The BIND 9 Lightweight Resolver for more +information. +4.8.1 Address Lookups Using AAAA Records -3 13 8 24 16 64 bits -FP TLA ID RES NLA ID SLA ID Interface ID -<------ Public Topology ------> - <-Site Topology-> - <------ Interface Identifier ------> - -Where - -FP = Format Prefix (001) -TLA ID = Top-Level Aggregation Identifier -RES = Reserved for future use -NLA ID = Next-Level Aggregation Identifier -SLA ID = Site-Level Aggregation Identifier -INTERFACE ID = Interface Identifier - - -The Public Topology is provided by the upstream provider or ISP, and (roughly) -corresponds to the IPv4 network section of the address range. The Site Topology is -where you can subnet this space, much like subnetting an IPv4 class A or B network -into class Cs. The Interface Identifier is the address of an individual interface on a -given network. (With IPv6, addresses belong to interfaces rather than machines.) - -The subnetting capability of IPv6 is much more flexible than that of IPv4: -subnetting can now be carried out on bit boundaries, in much the same way as -Classless InterDomain Routing (CIDR). - -The internal structure of the Public Topology for an A6 global unicast address -consists of: - - - -3 13 8 24 -FP TLA ID RES NLA ID - - -A 3 bit FP (Format Prefix) of 001 indicates this is a global Unicast address. FP -lengths for other types of addresses may vary. - -13 TLA (Top Level Aggregator) bits give the prefix of your top-level IP backbone -carrier. - -8 Reserved bits - -24 bits for Next Level Aggregators. This allows organizations with a TLA to hand -out portions of their IP space to client organizations, so that the client can then split -up the network further by filling in more NLA bits, and hand out IPv6 prefixes to -their clients, and so forth. - -There is no particular structure for the Site topology section. Organizations can -allocate these bits in any way they desire, in the same way as they would subnet an -IPv4 class A (8-bit prefix) network. - -The Interface Identifier must be unique on that network. On ethernet networks, one -way to ensure this is to set the address to the first three bytes of the hardware -address, "FFFE", then the last three bytes of the hardware address. The lowest -significant bit of the first byte should then be complemented. Addresses are written -as 32-bit blocks separated with a colon, and leading zeros of a block may be -omitted, for example: - -3ffe:8050:201:9:a00:20ff:fe81:2b32 - -IPv6 address specifications are likely to contain long strings of zeros, so the -architects have included a shorthand for specifying them. The double colon (`::') -indicates the longest possible string of zeros that can fit, and can be used only once -in an address. - -4.7.2 Name to Address Lookup - -Forward name lookups (host name to IP address) under IPv6 do not necessarily -return the complete IPv6 address of the host. Because the provider-assigned prefix -may change, the A6 record can simply specify the locally assigned portion of the -name, and refer to the provider for the remainder. - -This is an example of a complete IPv6 A6 record that provides the full 128 bit -address: +The AAAA record is a parallel to the IPv4 A record. It specifies the entire +address in a single record. For example, $ORIGIN example.com. - -; NAME TTL TYPE BITS IN REFERRAL ADDRESS REFERRAL -host.example.com. 1h IN A6 0 3ffe:8050:201:9:a00:20ff:fe81:2b32 . +host 1h IN AAAA 3ffe:8050:201:1860:42::1 +While their use is deprecated, they are useful to support older IPv6 +applications. They should not be added where they are not absolutely +necessary. -Note that the number preceding the address is the number of bits to be provided via -the referral. This is probably the easiest way to roll out an IPv6 installation, though -you may wish to provide a reference to your provider assigned prefix: +4.8.2 Address Lookups Using A6 Records + +The A6 record is more flexible than the AAAA record, and is therefore more +complicated. The A6 record can be used to form a chain of A6 records, each +specifying part of the IPv6 address. It can also be used to specify the +entire record as well. For example, this record supplies the same data as +the AAAA record in the previous example: $ORIGIN example.com. - -; NAME TTL TYPE BITS IN REFERRAL ADDRESS REFERRAL +host 1h IN A6 0 3ffe:8050:201:1860:42::1 -host.example.com. 1h IN A6 48 ::9:a00:20ff:fe81:2b32 prefix.example2.com. +4.8.2.1 A6 Chains +A6 records are designed to allow network renumbering. This works when an A6 +record only specifies the part of the address space the domain owner +controls. For example, a host may be at a company named "company." It has +two ISPs which provide IPv6 address space for it. These two ISPs fully +specify the IPv6 prefix they supply. -Then, in example2.com's zone: +In the company's address space: $ORIGIN example.com. - -; NAME TTL TYPE BITS IN REFERRAL ADDRESS REFERRAL -prefix.example2.com. 1h IN A6 0 3ffe:8050:201:: . +host 1h IN A6 64 0:0:0:0:42::1 company.example1.net. +host 1h IN A6 64 0:0:0:0:42::1 company.example2.net. +ISP1 will use: -The referral where there are no more bits is to ".", the root zone. Be warned that -excessive use of this chaining can lead to extremely poor name resolution for people -trying to access your hosts. +$ORIGIN example1.net. +company 1h IN A6 0 3ffe:8050:201:1860:: -4.7.3 Address to Name Lookup +ISP2 will use: -Reverse IPv6 addresses may appear as one or more hex strings, known as "bitstring -labels," each followed by a number of valid bits. A full 128 bits may be specified at -the ip6.int top level, or more likely, the provider will delegate you a smaller chunk of -addresses for which you will need to supply reverse DNS. +$ORIGIN example2.net. +company 1h IN A6 0 1234:5678:90ab:fffa:: -The address can be split up along arbitrary boundaries, and is written with hex -numbers in forward order, rather than in reverse order as IPv4 PTR records are -written. The sections between dot separators are reversed as usual. If the number of -valid bits in the hex string is less than the string specifies, it is the first N bits that are -counted. Thus, \[x2/3] gives a bit pattern of 0010, the first three bits of which, 001, -are valid. +When host.example.com is looked up, the resolver (in the resolver daemon or +caching name server) will find two partial A6 records, and will use the +additional name to find the remainder of the data. -The address above, then, is: +4.8.2.2 A6 Records for DNS Servers -\[x3FFE8050020100090A0020FFFE812B32/128].ip6.int. (not divided) +When an A6 record specifies the address of a name server, it should use the +full address rather than specifying a partial address. For example: -\[x00090A0020FFFE812B32/80].\[xFFF402801008/45].\[x2/3].ip6.int. (divided into FP, -TLA/RES/NLA, and local) +$ORIGIN example.com. +@ 4h IN NS ns0 + 4h IN NS ns1 -\[x00090A0020FFFE812B32/80].\[x80500201/32].\[xFFF0/13].\[x2/3].ip6.int. (divided -into FP, TLA, RES/NLA, and local) +ns0 4h IN A6 0 3ffe:8050:201:1860:42::1 +ns1 4h IN A 192.168.42.1 -These strings are all equivalent. The combined TLA/RES/NLA in the second -example bears no resemblance to any string in the address because it is offset by -three bits. +It is recommended that IPv4-in-IPv6 mapped addresses not be used. If a host +has an IPv4 address, use an A record, not an A6, with ::ffff:192.168.42.1 as +the address. -4.7.4 Using DNAME for Delegation of IPv6 Reverse Addresses +4.8.3 Address to Name Lookups Using Nibble Format -Delegation of reverse addresses is done through the new DNAME RR. In the -example above, where \[x2/3].ip6.int. needs to delegate \[xFFF0] to an -organization (example2.com), the domain administrator would insert a line similar -to the following in the \[x2/3].ip6.int. zone: +While the use of nibble format to look up names is deprecated, it is +supported for backwards compatiblity with existing IPv6 applications. + +When looking up an address in nibble format, the address components are +simply reversed, just as in IPv4, and ip6.int. is appended to the resulting +name. For example, the following would provide reverse name lookup for a +host with address 3ffe:8050:201:1860:42::1 . + +$ORIGIN 0.6.8.1.1.0.2.0.0.5.0.8.e.f.f.3.ip6.int. +1.0.0.0.0.0.0.0.0.0.0.0.2.4.0.0 4h IN PTR host.example.com. + +4.8.4 Address to Name Lookups Using Bitstring Format + +Bitstring labels can start and end on any bit boundary, rather than on a +multiple of 4 bits as in the nibble format. They also use ip6.arpa rather +than ip6.int . + +To replicate the previous example using bitstrings: + +$ORIGIN \[x3ffe805002011860/64].ip6.arpa. +\[x0042000000000001/64] 4h IN PTR host.example.com. + +4.8.5 Using DNAME for Delegation of IPv6 Reverse Addresses + +Delegation of reverse addresses is done through the new DNAME RR. In the +example above, where \[x2/3].ip6.int. needs to delegate \[xFFF0] to an +organization ( example2.com ), the domain administrator would insert a line +similar to the following in the \[x2/3].ip6.int. zone: $ORIGIN \[x2/3].ip6.int. \[xFFF0/13] 1h IN DNAME ip6.example2.com. @@ -1309,643 +1336,615 @@ Finally, example.com needs to include in the ip6.example.com zone: $ORIGIN ip6.example.com. \[x00090A0020FFFE812B32/80] 1h IN PTR host.example.com. -We suggest that the top of your administrative control (example.com, in this case) -provide all the bits required for reverse and forward resolution to allow name -resolution even if the network is disconnected from the Internet. This will also allow -operation with DNSSEC if you set up a false trusted server for "." containing only -delegations for your forward and reverse zones directly to the top of your -administrative control. This should be signed with a key trusted by all of your -clients, equivalent to the real key for ".". +We suggest that the top of your administrative control ( example.com , in +this case) provide all the bits required for reverse and forward resolution +to allow name resolution even if the network is disconnected from the +Internet. This will also allow operation with DNSSEC if you set up a false +trusted server for "." containing only delegations for your forward and +reverse zones directly to the top of your administrative control. This +should be signed with a key trusted by all of your clients, equivalent to +the real key for ".". + + ------------------------------------------------------------------------ + + Section 5. The BIND 9 Lightweight Resolver + + 5.1 The Lightweight Resolver Library + +Traditionally applications have been linked with a stub resolver library +that sends recursive DNS queries to a local caching name server. + +IPv6 introduces new complexity into the resolution process, such as +following A6 chains and DNAME records, and simultaneous lookup of IPv4 and +IPv6 addresses. These are hard or impossible to implement in a traditional +stub resolver. + +Instead, BIND 9 provides resolution services to local clients using a +combination of a lightweight resolver library and a resolver daemon process +running on the local host. These communicate using a simple UDP-based +protocol, the "lightweight resolver protocol" that is distinct from and +simpler than the full DNS protocol. + + 5.2 Running a Resolver Daemon + +To use the lightweight resolver interface, the system must run the resolver +daemon lwresd . + +Applications using the lightweight resolver library will make UDP requests +to the IPv4 loopback address (127.0.0.1) on port 921. The daemon will try to +find the answer to the questions "what are the addresses for host +foo.example.com ?" and "what are the names for IPv4 address 204.152.184.79?" + +The daemon currently only looks in the DNS, but in the future it may use +other sources such as /etc/hosts , NIS, etc. + +The lwresd daemon is essentially a stripped-down, caching-only name server +that answers requests using the lightweight resolver protocol rather than +the DNS protocol. Because it needs to run on each host, it is designed to +require no or minimal configuration. It uses the name servers listed on +nameserver lines in /etc/resolv.conf as forwarders, but is also capable of +doing the resolution autonomously if none are specified. + + ------------------------------------------------------------------------ + +Section 6. BIND 9 Configuration Reference + +BIND 9 configuration is broadly similar to BIND 8.x; however, there are a +few new areas of configuration, such as views. BIND 8.x configuration files +should work with few alterations in BIND 9, although more complex +configurations should be reviewed to check if they can be more efficiently +implemented using the new features found in BIND 9. + +BIND 4 configuration files can be converted to the new format using the +shell script +contrib/named-bootconf/named-bootconf.sh . + +6.1 Configuration File Elements + +Following is a list of elements used throughout the BIND configuration file +documentation: -Section 5. BINDv9 Configuration Reference + acl_name The name of an address_match_list as defined by the acl + statement. -BINDv9 configuration is broadly similar to BIND 8.x; however, there are a few new areas of -configuration, such as views. BIND 8.x configuration files should work with few alterations -in BINDv9, although more complex configurations should be reviewed to check if they can -be more efficiently implemented using the new features found in BINDv9. + address_match_list A list of one or more ip_addr , ip_prefix , key_id , or + acl_name elements, as described in Address Match Lists + . + domain_name A quoted string which will be used as a DNS name, for + example " my.test.domain ". -BIND 4.9.x configuration files can be converted to the new format by using the Perl script -src/bin/named/named-bootconf.pl from the BIND 8 release kit. + dotted_decimal One or more integers valued 0 through 255 separated + only by dots (`.'), such as 123 , 45.67 or 89.123.45.67 + . + ip4_addr An IPv4 address with exactly four elements in + dotted_decimal notation. + ip6_addr + An IPv6 address, such as fe80::200:f8ff:fe01:9742 . -5.1 Configuration file elements + ip_addr + An ip4_addr or ip6_addr . -Following is a list of elements used throughout the BIND configuration file documentation: + An IP port number . number is limited to 0 through + ip_port 65535, with values below 1024 typically restricted to + root-owned processes. In some cases an asterisk (`*') + character can be used as a placeholder to select a + random high-numbered port. + An IP network specified as an ip_addr , followed by a + ip_prefix slash (`/') and then the number of bits in the netmask. + For example, 127/8 is the network 127.0.0.0 with + netmask 255.0.0.0 and 1.2.3.0/28 is network 1.2.3.0 + with netmask 255.255.255.240 . + key_name A domain_name representing the name of a shared key, to + be used for transaction security. + A non-negative integer with an entire range limited by + number the range of a C language signed integer (2,147,483,647 + on a machine with 32 bit integers). Its acceptable + value might further be limited by the context in which + it is used. + path_name A quoted string which will be used as a pathname, such + as " zones/master/my.test.domain " . + A number, the word unlimited , or the word default . + The maximum value of size_spec is that of unsigned long + integers on the machine. An unlimited size_spec + requests unlimited use, or the maximum available + amount. A default size_spec uses the limit that was in + force when the server was started. + size_spec A number can optionally be followed by a scaling + factor: K or k for kilobytes, M or m for megabytes, and + G or g for gigabytes, which scale by 1024, 1024*1024, + and 1024*1024*1024 respectively. -acl_name - The name of an address_match_list as defined by the acl -statement. + Integer storage overflow is currently silently ignored + during conversion of scaled values, resulting in values + less than intended, possibly even negative. Using + unlimited is the best way to safely set a really large + number. + yes_or_no Either yes or no . The words true and false are also + accepted, as are the numbers 1 and 0 . -address_match_list - A list of one or more ip_addr, ip_prefix, key_id, or -acl_name elements, as described in "Address Match Lists" -on page 28. +6.1.1 Address Match Lists -domain_name - A quoted string which will be used as a DNS name, for -example "my.test.domain". - -dotted_decimal - One or more integers valued 0 through 255 separated only -by dots (`.'), such as 123, 45.67 or 89.123.45.67. - -ip4_addr - An IPv4 address with exactly four elements in -dotted_decimal notation. - -ip6_addr - An IPv6 address, like fe80::200:f8ff:fe01:9742. - -ip_addr - An ip4_addr or ip6_addr. - -ip_port - An IP port number. number is limited to 0 through 65535, -with values below 1024 typically restricted to root-owned -processes. In some cases an asterisk (`*') character can be -used as a placeholder to select a random high-numbered -port. - -ip_prefix - An IP network specified as an ip_addr, followed by a slash -(`/') and then the number of bits in the netmask. For -example, 127/8 is the network 127.0.0.0 with netmask -255.0.0.0 and 1.2.3.0/28 is network 1.2.3.0 with -netmask 255.255.255.240. - -key_name - A domain_name representing the name of a shared key, to be -used for transaction security. - -number - A non-negative integer with an entire range limited by the -range of a C language signed integer (2,147,483,647 on a -machine with 32 bit integers). Its acceptable value might -further be limited by the context in which it is used. - -path_name - A quoted string which will be used as a pathname, such as -"zones/master/my.test.domain". - -size_spec - A number, the word unlimited, or the word default. - -The maximum value of size_spec is that of unsigned long -integers on the machine. An unlimited size_spec requests -unlimited use, or the maximum available amount. A default -size_spec uses the limit that was in force when the server -was started. - -A number can optionally be followed by a scaling factor: K -or k for kilobytes, M or m for megabytes, and G or g for -gigabytes, which scale by 1024, 1024*1024, and -1024*1024*1024 respectively. - -Integer storage overflow is currently silently ignored during -conversion of scaled values, resulting in values less than -intended, possibly even negative. Using unlimited is the best -way to safely set a really large number. - -yes_or_no - Either yes or no. The words true and false are also -accepted, as are the numbers 1 and 0. - - -5.1.1 Address Match Lists - -5.1.1.1 Syntax +6.1.1.1 Syntax address_match_list = address_match_list_element ; - [ address_match_list_element; ... ] +[ address_match_list_element; ... ] address_match_list_element = [ ! ] (ip_address [/length] | - key key_id | acl_name | { address_match_list } ) +key key_id | acl_name | { address_match_list } ) -5.1.1.2 Definition and Usage +6.1.1.2 Definition and Usage -Address match lists are primarily used to determine access control for -various server operations. They are also used to define priorities for -querying other nameservers and to set the addresses on which named will -listen for queries. The elements which constitute an address match list can +Address match lists are primarily used to determine access control for +various server operations. They are also used to define priorities for +querying other nameservers and to set the addresses on which named will +listen for queries. The elements which constitute an address match list can be any of the following: -o an IP address (IPv4 or IPv6) + * an IP address (IPv4 or IPv6) + * an IP prefix (in the `/'-notation) + * a key ID, as defined by the key statement + * the name of an address match list previously defined with the acl + statement + * a nested address match list enclosed in braces -o an IP prefix (in the `/'-notation) +Elements can be negated with a leading exclamation mark (`!') and the match +list names "any," "none," "localhost" and "localnets" are predefined. More +information on those names can be found in the description of the acl +statement. -o a key ID, as defined by the key statement +The addition of the key clause made the name of this syntactic element +something of a misnomer, since security keys can be used to validate access +without regard to a host or network address. Nonetheless, the term "address +match list" is still used throughout the documentation. -o the name of an address match list previously defined with the acl -statement +When a given IP address or prefix is compared to an address match list, the +list is traversed in order until an element matches. The interpretation of a +match depends on whether the list is being used for access control, defining +listen-on ports, or as a topology, and whether the element was negated. -o a nested address match list enclosed in braces +When used as an access control list, a non-negated match allows access and a +negated match denies access. If there is no match, access is denied. The +clauses allow-query , allow-transfer , allow-update and blackhole all use +address match lists this. Similarly, the listen-on option will cause the +server to not accept queries on any of the machine's addresses which do not +match the list. -Elements can be negated with a leading exclamation mark (`!') and the -match list names "any," "none," "localhost" and "localnets" are -predefined. More information on those names can be found in the -description of the acl statement. +When used with the topology clause, a non-negated match returns a distance +based on its position on the list (the closer the match is to the start of +the list, the shorter the distance is between it and the server). A negated +match will be assigned the maximum distance from the server. If there is no +match, the address will get a distance which is further than any non-negated +list element, and closer than any negated element. -The addition of the key clause made the name of this syntactic element -something of a misnomer, since security keys can be used to validate -access without regard to a host or network address. Nonetheless, the term -"address match list" is still used throughout the documentation. - -When a given IP address or prefix is compared to an address match list, -the list is traversed in order until an element matches. The interpretation -of a match depends on whether the list is being used for access control, -defining listen-on ports, or as a topology, and whether the element was -negated. - -When used as an access control list, a non-negated match allows access -and a negated match denies access. If there is no match, access is denied. -The clauses allow-query, allow-transfer, allow-update and blackhole all -use address match lists like this. Similarly, the listen-on option will cause -the server to not accept queries on any of the machine's addresses which -do not match the list. - -When used with the topology clause, a non-negated match returns a -distance based on its position on the list (the closer the match is to the -start of the list, the shorter the distance is between it and the server). A -negated match will be assigned the maximum distance from the server. If -there is no match, the address will get a distance which is further than any -non-negated list element, and closer than any negated element. - -Because of the first-match aspect of the algorithm, an element that defines -a subset of another element in the list should come before the broader +Because of the first-match aspect of the algorithm, an element that defines +a subset of another element in the list should come before the broader element, regardless of whether either is negated. For example, in -1.2.3/24; ! 1.2.3.13; the 1.2.3.13 element is completely useless -because the algorithm will match any lookup for 1.2.3.13 to the 1.2.3/24 -element. Using ! 1.2.3.13; 1.2.3/24 fixes that problem by having -1.2.3.13 blocked by the negation but all other 1.2.3.* hosts fall through. +1.2.3/24; ! 1.2.3.13; the 1.2.3.13 element is completely useless because the +algorithm will match any lookup for 1.2.3.13 to the 1.2.3/24 element. Using +! 1.2.3.13; 1.2.3/24 fixes that problem by having 1.2.3.13 blocked by the +negation but all other 1.2.3.* hosts fall through. -5.1.2 Comment Syntax +6.1.2 Comment Syntax -The BINDv9 comment syntax allows for comments to appear anywhere that white space -may appear in a BIND configuration file. To appeal to programmers of all kinds, they can be -written in C, C++, or shell/perl constructs. +The BIND 9 comment syntax allows for comments to appear anywhere that white +space may appear in a BIND configuration file. To appeal to programmers of +all kinds, they can be written in C, C++, or shell/perl constructs. -5.1.2.1 Syntax +6.1.2.1 Syntax /* This is a BIND comment as in C */ // This is a BIND comment as in C++ # This is a BIND comment as in common UNIX shells and perl -5.1.2.2 Definition and Usage +6.1.2.2 Definition and Usage -Comments may appear anywhere that whitespace may appear in a BIND +Comments may appear anywhere that whitespace may appear in a BIND configuration file. -C-style comments start with the two characters /* (slash, star) and end with */ (star, -slash). Because they are completely delimited with these characters, they can be -used to comment only a portion of a line or to span multiple lines. +C-style comments start with the two characters /* (slash, star) and end with +*/ (star, slash). Because they are completely delimited with these +characters, they can be used to comment only a portion of a line or to span +multiple lines. -C-style comments cannot be nested. For example, the following is not valid because -the entire comment ends with the first */: +C-style comments cannot be nested. For example, the following is not valid +because the entire comment ends with the first */: /* This is the start of a comment. - This is still part of the comment. +This is still part of the comment. /* This is an incorrect attempt at nesting a comment. */ - This is no longer in any comment. */ +This is no longer in any comment. */ -C++-style comments start with the two characters // (slash, slash) and continue to -the end of the physical line. They cannot be continued across multiple physical -lines; to have one logical comment span multiple lines, each line must use the // pair. +C++-style comments start with the two characters // (slash, slash) and +continue to the end of the physical line. They cannot be continued across +multiple physical lines; to have one logical comment span multiple lines, +each line must use the // pair. For example: -// This is the start of a comment. The next line +// This is the start of a comment. The next line // is a new comment, even though it is logically // part of the previous comment. -Shell-style (or perl-style, if you prefer) comments start with the character # (number -sign) and continue to the end of the physical line, like C++ comments. +Shell-style (or perl-style, if you prefer) comments start with the character +# (number sign) and continue to the end of the physical line, as in C++ +comments. For example: -# This is the start of a comment. The next line +# This is the start of a comment. The next line # is a new comment, even though it is logically # part of the previous comment. -WARNING: you cannot use the semicolon (`;') character to start a comment such as -you would in a zone file. The semicolon indicates the end of a configuration -statement. +WARNING: you cannot use the semicolon (`;') character to start a comment +such as you would in a zone file. The semicolon indicates the end of a +configuration statement. -5.2 Configuration File Grammar +6.2 Configuration File Grammar -A BINDv9 configuration consists of statements and comments. Statements end with a -semicolon. Statements and comments are the only elements that can appear without -enclosing braces. Many statements contain a block of substatements, which are also -terminated with a semicolon. +A BIND 9 configuration consists of statements and comments. Statements end +with a semicolon. Statements and comments are the only elements that can +appear without enclosing braces. Many statements contain a block of +substatements, which are also terminated with a semicolon. The following statements are supported: -acl - defines a named IP address matching list, for access control -and other uses. + acl defines a named IP address matching list, for access control + and other uses. + controls declares control channels to be used by the rndc utility. + include includes a file. -controls - declares control channels to be used by the rndc utility. + key specifies key information for use in authentication and + authorization using TSIG. -include - includes a file. - -key - specifies key information for use in authentication and -authorization using TSIG. - -logging - specifies what the server logs, and where the log messages -are sent. - -options - controls global server configuration options and sets -defaults for other statements. - -server - sets certain configuration options on a per-server basis. - -trusted-keys - defines trusted DNSSEC keys. - -view - defines a view. - -zone - defines a zone. + logging specifies what the server logs, and where the log messages + are sent. + options controls global server configuration options and sets + defaults for other statements. + server sets certain configuration options on a per-server basis. + trusted-keys defines trusted DNSSEC keys. + view defines a view. + zone defines a zone. The logging and options statements may only occur once per configuration. -5.2.1 acl Statement Grammar +6.2.1 acl Statement Grammar -acl acl-name { - address_match_list +acl acl-name { + address_match_list }; -5.2.2 acl Statement Definition and Usage +6.2.2 acl Statement Definition and Usage -The acl statement assigns a symbolic name to an address match list. It gets its name -from a primary use of address match lists: Access Control Lists (ACLs). +The acl statement assigns a symbolic name to an address match list. It gets +its name from a primary use of address match lists: Access Control Lists +(ACLs). -Note that an address match list's name must be defined with acl before it can be -used elsewhere; no forward references are allowed. +Note that an address match list's name must be defined with acl before it +can be used elsewhere; no forward references are allowed. The following ACLs are built-in: -any - Matches all hosts. + any Matches all hosts. + none Matches no hosts. + localhost Matches the IP addresses of all interfaces on the system. -none - Matches no hosts. + localnets Matches any host on a network for which the system has an + interface. -localhost - Matches the IP addresses of all interfaces on the system. - -localnets - Matches any host on a network for which the system has an -interface. - - -5.2.3 controls Statement Grammar +6.2.3 controls Statement Grammar controls { [ inet (ip_addr|*) port ip_port allow { address_match_list } ; - [ inet...;[...]]] + [ inet...;[...]]] [ unix string permission number owner number group number ; - [ unix...;[..]]] + [ unix...;[..]]] }; -5.2.4 controls Statement Definition and Usage +6.2.4 controls Statement Definition and Usage -The controls statement declares control channels to be used by system -administrators to affect the operation of the local nameserver. These control -channels are used by the ndc utility to send commands to and retrieve non-DNS -results from a nameserver. +The controls statement declares control channels to be used by system +administrators to affect the operation of the local nameserver. These +control channels are used by the ndc utility to send commands to and +retrieve non-DNS results from a nameserver. -A UNIX control channel is a "first in first out" (FIFO) named pipe in the file system, -and access to it is controlled by normal file system permissions. It is created by -named with the specified file mode bits (see the chmod(1) manual page), user and -group owner. Note that, unlike chmod, the mode bits specified for permission will -normally have a leading 0 so the number is interpreted as octal. Also note that the -user and group ownership specified as owner and group must be given as numbers, -not names. It is recommended that the permissions be restricted to administrative -personnel only to prevent random users on the system from having the ability to -manage the local nameserver. +A UNIX control channel is a "first in first out" (FIFO) named pipe in the +file system, and access to it is controlled by normal file system +permissions. It is created by named with the specified file mode bits (see +the chmod(1) manual page), user and group owner. Note that, unlike chmod , +the mode bits specified for permission will normally have a leading 0 so the +number is interpreted as octal. Also note that the user and group ownership +specified as owner and group must be given as numbers, not names. It is +recommended that the permissions be restricted to administrative personnel +only to prevent random users on the system from having the ability to manage +the local nameserver. -An inet control channel is a TCP/IP socket accessible to the Internet, created at the -specified ip_port on the specified ip_addr. It is recommended that 127.0.0.1 be the -only ip_addr used, and this only if you trust all non-privileged users on the local -host to manage your nameserver. +An inet control channel is a TCP/IP socket accessible to the Internet, +created at the specified ip_port on the specified ip_addr . It is +recommended that 127.0.0.1 be the only ip_addr used, and this only if you +trust all non-privileged users on the local host to manage your nameserver. -The controls statement is not yet implemented in BINDv9. The server always +The controls statement is not yet implemented in BIND 9. The server always listens for control connections on IP address 127.0.0.1, port 953. -5.2.5 include Statement Grammar +6.2.5 include Statement Grammar -include filename; +include filename ; -5.2.6 include Statement Definition and Usage +6.2.6 include Statement Definition and Usage -The include statement inserts the specified file at the point that the include -statement is encountered. The include statement facilitates the administration of -configuration files by permitting the reading or writing of some things but not -others. For example, the statement could include private keys that are readable only -by a nameserver. +The include statement inserts the specified file at the point that the +include statement is encountered. The include statement facilitates the +administration of configuration files by permitting the reading or writing +of some things but not others. For example, the statement could include +private keys that are readable only by a nameserver. -5.2.7 key Statement Grammar +6.2.7 key Statement Grammar key key_id { - algorithm string; - secret string; +algorithm string; +secret string; }; -5.2.8 key Statement Definition and Usage +6.2.8 key Statement Definition and Usage -The key statement defines a shared secret key for use with TSIG. See Section 4.4, -"TSIG", on page 17. +The key statement defines a shared secret key for use with TSIG. See TSIG . -The key_id, also known as the key name, is a domain name uniquely identifying the -key. It can be used in a "server" statement to cause requests sent to that server to be -signed with this key, or in address match lists to verify that incoming requests have -been signed with a key matching this name, algorithm, and secret. +The key_id , also known as the key name, is a domain name uniquely +identifying the key. It can be used in a "server" statement to cause +requests sent to that server to be signed with this key, or in address match +lists to verify that incoming requests have been signed with a key matching +this name, algorithm, and secret. -The algorithm_id is a string that specifies a security/authentication algorithm. The -only algorithm currently supported with TSIG authentication is hmac-md5. The -secret_string is the secret to be used by the algorithm, and is treated as a base-64 -encoded string. +The algorithm_id is a string that specifies a security/authentication +algorithm. The only algorithm currently supported with TSIG authentication +is hmac-md5 . The secret_string is the secret to be used by the algorithm, +and is treated as a base-64 encoded string. -5.2.9 logging Statement Grammar +6.2.9 logging Statement Grammar logging { [ channel channel_name { ( file path name [ versions ( number | unlimited ) ] [ size size spec ] - | syslog ( syslog_facility ) + | syslog ( syslog_facility | null ); [ severity (critical | error | warning | notice | - info | debug [ level ] | dynamic ); ] - [ print-category yes or no; ] + info | debug [ level ] | dynamic ; ] + [ print-category yes or no; [ print-severity yes or no; ] [ print-time yes or no; ] - }; ] - [ category category_name { - channel_name ; [ channel_name ; ... ] - }; ] - ... - + ... }; -5.2.10 logging Statement Definition and Usage - -The logging statement configures a wide variety of logging options for the -nameserver. Its channel phrase associates output methods, format options and -severity levels with a name that can then be used with the category phrase to select -how various classes of messages are logged. - -Only one logging statement is used to define as many channels and categories as -are wanted. If there is no logging statement, the logging configuration will be: +6.2.10 logging Statement Definition and Usage +The logging statement configures a wide variety of logging options for the +nameserver. Its channel phrase associates output methods, format options and +severity levels with a name that can then be used with the category phrase +to select how various classes of messages are logged. +Only one logging statement is used to define as many channels and categories +as are wanted. If there is no logging statement, the logging configuration +will be: logging { - category default { default_syslog; default_debug; }; + category "default" { "default_syslog"; "default_debug"; }; + }; - }; +In BIND 9, the logging configuration is only established when the entire +configuration file has been parsed. In BIND 8, it was established as soon as +the logging statement was parsed. When the server is starting up, all +logging messages regarding syntax errors in the configuration file go to the +default channels, or to standard error if the " -g " option was specified. -In BINDv9, the logging configuration is only established when the entire -configuration file has been parsed. In BIND 8, it was established as soon as the -logging statement was parsed. When the server is starting up, all logging messages -regarding syntax errors in the configuration file go to the default channels, or to -standard error if the "-g" option was specified. +6.2.10.1 The channel Phrase -5.2.10.1 The channel Phrase +All log output goes to one or more channels ; you can make as many of them +as you want. -All log output goes to one or more channels; you can make as many of -them as you want. +Every channel definition must include a clause that says whether messages +selected for the channel go to a file, to a particular syslog facility, or +are discarded. It can optionally also limit the message severity level that +will be accepted by the channel (the default is info ), and whether to +include a named -generated time stamp, the category name and/or severity +level (the default is not to include any). -Every channel definition must include a clause that says whether -messages selected for the channel go to a file, to a particular syslog -facility, or are discarded. It can optionally also limit the message severity -level that will be accepted by the channel (the default is info), and -whether to include a named-generated time stamp, the category name and/ -or severity level (the default is not to include any). - -The word null as the destination option for the channel will cause all -messages sent to it to be discarded; in that case, other options for the +The word null as the destination option for the channel will cause all +messages sent to it to be discarded; in that case, other options for the channel are meaningless. -The file clause can include limitations both on how large the file is -allowed to become, and how many versions of the file will be saved each -time the file is opened. +The file clause can include limitations both on how large the file is +allowed to become, and how many versions of the file will be saved each time +the file is opened. -The size option for files is simply a hard ceiling on log growth. If the file -ever exceeds the size, then named will not write anything more to it until -the file is reopened; exceeding the size does not automatically trigger a -reopen. The default behavior is not to limit the size of the file. +The size option for files is simply a hard ceiling on log growth. If the +file ever exceeds the size, then named will not write anything more to it +until the file is reopened; exceeding the size does not automatically +trigger a reopen. The default behavior is not to limit the size of the file. -If you use the version log file option, then named will retain that many -backup versions of the file by renaming them when opening. For example, -if you choose to keep 3 old versions of the file lamers.log then just -before it is opened lamers.log.1 is renamed to lames.log.2, -lamers.log.0 is renamed to lamers.log.1, and lamers.log is renamed -to lamers.log.0. No rolled versions are kept by default; any existing log -file is simply appended. The unlimited keyword is synonymous with 99 -in current BIND releases. +If you use the version log file option, then named will retain that many +backup versions of the file by renaming them when opening. For example, if +you choose to keep 3 old versions of the file lamers.log then just before it +is opened lamers.log.1 is renamed to lamers.log.2 , lamers.log.0 is renamed +to lamers.log.1 , and lamers.log is renamed to lamers.log.0 . No rolled +versions are kept by default; any existing log file is simply appended. The +unlimited keyword is synonymous with 99 in current BIND releases. Example usage of the size and versions options: - channel an_example_level { - file "lamers.log" versions 3 size 20m; + channel "an_example_channel" { + file "example.log" versions 3 size 20m; print-time yes; print-category yes; }; -The argument for the syslog clause is a syslog facility as described in the -syslog man page. How syslog will handle messages sent to this facility -is described in the syslog.conf man page. If you have a system which -uses a very old version of syslog that only uses two arguments to the -openlog() function, then this clause is silently ignored. +The argument for the syslog clause is a syslog facility as described in the +syslog man page. How syslog will handle messages sent to this facility is +described in the syslog.conf man page. If you have a system which uses a +very old version of syslog that only uses two arguments to the openlog() +function, then this clause is silently ignored. -The severity clause works like syslog's "priorities," except that they -can also be used if you are writing straight to a file rather than using -syslog. Messages which are not at least of the severity level given will -not be selected for the channel; messages of higher severity levels will be +The severity clause works like syslog 's "priorities," except that they can +also be used if you are writing straight to a file rather than using syslog +. Messages which are not at least of the severity level given will not be +selected for the channel; messages of higher severity levels will be accepted. -If you are using syslog, then the syslog.conf priorities will also -determine what eventually passes through. For example, defining a -channel facility and severity as daemon and debug but only logging -daemon.warning via syslog.conf will cause messages of severity info -and notice to be dropped. If the situation were reversed, with named -writing messages of only warning or higher, then syslogd would print all -messages it received from the channel. +If you are using syslog , then the syslog.conf priorities will also +determine what eventually passes through. For example, defining a channel +facility and severity as daemon and debug but only logging daemon.warning +via syslog.conf will cause messages of severity info and notice to be +dropped. If the situation were reversed, with named writing messages of only +warning or higher, then syslogd would print all messages it received from +the channel. -The server can supply extensive debugging information when it is in -debugging mode. If the server's global debug level is greater than zero, -then debugging mode will be active. The global debug level is set either -by starting the named server with the "-d" flag followed by a positive -integer, or by running rndc trace (the latter method is not yet -implemented). The global debug level can be set to zero, and debugging -mode turned off, by running ndc notrace. All debugging messages in the -server have a debug level, and higher debug levels give more detailed -output. Channels that specify a specific debug severity, for example: +The server can supply extensive debugging information when it is in +debugging mode. If the server's global debug level is greater than zero, +then debugging mode will be active. The global debug level is set either by +starting the named server with the " -d " flag followed by a positive +integer, or by running rndc trace ( the latter method is not yet implemented +). The global debug level can be set to zero, and debugging mode turned off, +by running ndc notrace . All debugging messages in the server have a debug +level, and higher debug levels give more detailed output. Channels that +specify a specific debug severity, for example: - channel specific_debug_level { + channel "specific_debug_level" { file "foo"; severity debug 3; }; -will get debugging output of level 3 or less any time the server is in -debugging mode, regardless of the global debugging level. Channels with -dynamic severity use the server's global level to determine what messages -to print. +will get debugging output of level 3 or less any time the server is in +debugging mode, regardless of the global debugging level. Channels with +dynamic severity use the server's global level to determine what messages to +print. -If print-time has been turned on, then the date and time will be logged. -print-time may be specified for a syslog channel, but is usually -pointless since syslog also prints the date and time. If print-category is -requested, then the category of the message will be logged as well. -Finally, if print-severity is on, then the severity level of the message -will be logged. The print- options may be used in any combination, and -will always be printed in the following order: time, category, severity. -Here is an example where all three print- options are on: +If print-time has been turned on, then the date and time will be logged. +print-time may be specified for a syslog channel, but is usually pointless +since syslog also prints the date and time. If print-category is requested, +then the category of the message will be logged as well. Finally, if +print-severity is on, then the severity level of the message will be logged. +The print- options may be used in any combination, and will always be +printed in the following order: time, category, severity. Here is an example +where all three print- options are on: 28-Feb-2000 15:05:32.863 general: notice: running -There are four predefined channels that are used for named's default -logging as follows. How they are used is described in "The category -Phrase" on page 36. +There are four predefined channels that are used for named 's default +logging as follows. How they are used is described in the category Phrase . - channel default_syslog { - syslog daemon; // end to syslog's daemon facility - severity info; // only send priority info and higher + channel "default_syslog" { + syslog daemon; // end to syslog's daemon + // facility + severity info; // only send priority info + // and higher }; - channel default_debug { - file "named.run"; // write to named.run in - // the working directory - // Note: stderr is used instead of - // "named.run" - // if the server is started - // with the '-f' option. - severity dynamic // log at the server's - // current debug level + channel "default_debug" { + file "named.run"; // write to named.run in + // the working directory + // Note: stderr is used instead + // of "named.run" + // if the server is started + // with the '-f' option. + severity dynamic // log at the server's + // current debug level }; - channel default_stderr { // writes to stderr - file ""; // this is illustrative only; - // there's currently no way of - // specifying an internal file - // descriptor in the configuration - // language. - severity info; // only send priority info and higher + channel "default_stderr" { // writes to stderr + file ""; // this is illustrative only; + // there's currently no way of + // specifying an internal file + // descriptor in the + // configuration language. + severity info; // only send priority info + // and higher }; - channel null { - null; // toss anything sent to this channel + channel "null" { + null; // toss anything sent to + // this channel }; -The default_debug channel normally writes to a file named.run in the -server's working directory. For security reasons, when the "-u" command -line option is used, the named.run file is created only after named has -changed to the new UID, and any debug output generated while named is -starting up and still running as root is discarded. If you need to capture -this output, you must run the server with the "-g" option and redirect +The default_debug channel normally writes to a file named.run in the +server's working directory. For security reasons, when the " -u " command +line option is used, the named.run file is created only after named has +changed to the new UID, and any debug output generated while named is +starting up and still running as root is discarded. If you need to capture +this output, you must run the server with the " -g " option and redirect standard error to a file. -Once a channel is defined, it cannot be redefined. Thus you cannot alter -the built-in channels directly, but you can modify the default logging by +Once a channel is defined, it cannot be redefined. Thus you cannot alter the +built-in channels directly, but you can modify the default logging by pointing categories at channels you have defined. -5.2.10.2 The category Phrase +6.2.10.2 The category Phrase -There are many categories, so you can send the logs you want to see -wherever you want, without seeing logs you don't want. If you don't -specify a list of channels for a category, then log messages in that -category will be sent to the default category instead. If you don't specify -a default category, the following "default default" is used: +There are many categories, so you can send the logs you want to see wherever +you want, without seeing logs you don't want. If you don't specify a list of +channels for a category, then log messages in that category will be sent to +the default category instead. If you don't specify a default category, the +following "default default" is used: - category default { default_syslog; default_debug; }; +category "default" { "default_syslog"; "default_debug"; }; -As an example, let's say you want to log security events to a file, but you +As an example, let's say you want to log security events to a file, but you also want keep the default logging behavior. You'd specify the following: -channel my_security_channel { +channel "my_security_channel" { file "my_security_file"; severity info; }; -category security { - my_security_channel; - default_syslog; - default_debug; +category "security" { + "my_security_channel"; + "default_syslog"; + "default_debug"; }; To discard all messages in a category, specify the null channel: -category xfer-out { null; }; -category notify { null; }; +category "xfer-out" { "null"; }; +category "notify" { "null"; }; -Following are the available categories and brief descriptions of the types -of log information they contain. This list is still subject to change. +Following are the available categories and brief descriptions of the types +of log information they contain . More categories may be added in future +BIND releases. -default - The default category defines the logging options for -those categories where no specific configuration has -been defined. If you do not define a default category, -the following definition is used: -category default { default_syslog; -default_debug; }; + default The default category defines the logging options for those + categories where no specific configuration has been defined. -general - The catch-all. Many things still aren't classified into -categories, and they all end up here. + general The catch-all. Many things still aren't classified into + categories, and they all end up here. -database - Messages relating to the databases used internally by -the name server to store zone and cache data. + database Messages relating to the databases used internally by the name + server to store zone and cache data. + security Approval and denial of requests. + config Configuration file parsing and processing. -security - Approval and denial of requests. + resolver DNS resolution, such as the recursive lookups performed on behalf + of clients by a caching name server. + xfer-in Zone transfers the server is receiving. + xfer-out Zone transfers the server is sending. + notify The NOTIFY protocol. + client Processing of client requests. + network Network operations. + update Dynamic updates. -config - Configuration file parsing and processing. - -resolver - DNS resolution, such as the recursive lookups -performed on behalf of clients by a caching name -server. - -xfer-in - Zone transfers the server is receiving. - -xfer-out - Zone transfers the server is sending. - -notify - The NOTIFY protocol. - -client - Processing of client requests. - -network - Network operations. - -update - Dynamic updates. - - -5.2.11 options Statement Grammar +6.2.11 options Statement Grammar This is the grammar of the option statement in the named.conf file: options { + [ version version_string; ] [ directory path_name; ] [ named-xfer path_name; ] @@ -1974,7 +1973,7 @@ options { [ allow-query { address_match_list }; ] [ allow-transfer { address_match_list }; ] [ allow-recursion { address_match_list }; ] - [ blackhole { address_match_list }; ] + [ blackhole { address_match_list }; ] [ listen-on [ port ip_port ] { address_match_list }; ] [ query-source [ address ( ip_addr | * ) ] [ port ( ip_port | * ) ]; ] [ max-transfer-time-in number; ] @@ -1988,301 +1987,216 @@ options { [ transfers-in number; ] [ transfers-out number; ] [ transfers-per-ns number; ] - [ transfer-source ip_addr; ] + [ transfer-source ip4_addr; ] + [ transfer-source-v6 ip6_addr; ] [ also-notify { ip_addr; [ ip_addr; ... ] }; ] - [ max-ixfr-log-size number; ] - [ coresize size_spec ; ] - [ datasize size_spec ; ] - [ files size_spec ; ] - [ stacksize size_spec ; ] - [ cleaning-interval number; ] - [ heartbeat-interval number; ] - [ interface-interval number; ] - [ statistics-interval number; ] + [ max-ixfr-log-size number; ] [ coresize size_spec ; ] [ datasize size_spec ; ] [ files size_spec ; ] [ stacksize size_spec ; ] [ cleaning-interval number; ] [ heartbeat-interval number; ] [ interface-interval number; ] [ statistics-interval number; ] [ topology { address_match_list }; ] [ sortlist { address_match_list }; ] - [ rrset-order { order_spec ; [ order_spec ; ... ] ] }; - [ lame-ttl number; ] - [ max-ncache-ttl number; ] + [ rrset-order { order_spec ; [ order_spec ; ... ] ] }; [ lame-ttl number; ] [ max-ncache-ttl number; ] + [ max-cache-ttl number; ] [ sig-validity-interval number ; ] [ min-roots number; ] [ use-ixfr yes_or_no ; ] [ treat-cr-as-space yes_or_no ; ] }; -5.2.12 options Statement Definition and Usage +6.2.12 options Statement Definition and Usage -The options statement sets up global options to be used by BIND. This statement -may appear only once in a configuration file. If more than one occurrence is found, -the first occurrence determines the actual options used, and a warning will be -generated. If there is no options statement, an options block with each option set to -its default will be used. +The options statement sets up global options to be used by BIND. This +statement may appear only once in a configuration file. If more than one +occurrence is found, the first occurrence determines the actual options +used, and a warning will be generated. If there is no options statement, an +options block with each option set to its default will be used. -version - The version the server should report via a query -of name version.bind in class chaos. The default is -the real version number of this server. + The version the server should report via a query of + version name version.bind in class chaos . The default is the + real version number of this server. + The working directory of the server. Any non-absolute + pathnames in the configuration file will be taken as + relative to this directory. The default location for + directory most server output files (e.g. named.run ) is this + directory. If a directory is not specified, the working + directory defaults to ` . ', the directory from which + the server was started. The directory specified should + be an absolute path. + This option is obsolete. It was used in BIND 8 to + named-xfer specify the pathname to the named-xfer program. In + BIND 9, no separate named-xfer program is needed; its + functionality is built into the name server. + The domain appended to the names of all shared keys + generated with TKEY . When a client requests a TKEY + exchange, it may or may not specify the desired name + tkey-domain for the key. If present, the name of the shared key + will be " client specified part " + " tkey-domain ". + Otherwise, the name of the shared key will be " random + hex digits " + " tkey-domain ". In most cases, the + domainname should be the server's domain name. + The Diffie-Hellman key used by the server to generate + shared keys with clients using the Diffie-Hellman mode + tkey-dhkey of TKEY . The server must be able to load the public + and private keys from files in the working directory. + In most cases, the keyname should be the server's host + name. + The pathname of the file the server dumps the database + dump-file to when it receives SIGINT signal ( ndc dumpdb ). If + not specified, the default is named_dump.db . Not yet + implemented in BIND 9. + The pathname of the file the server writes memory usage + memstatistics-file statistics to on exit. If not specified, the default is + named.memstats . Not yet implemented in BIND 9. + The pathname of the file the server writes its process + ID in. If not specified, the default is operating + pid-file system dependent, but is usually + /var/run/named.pid or /etc/named.pid . The pid-file is + used by programs that want to send signals to the + running nameserver. + The pathname of the file the server appends statistics + statistics-file to. If not specified, the default is named.stats . Not + yet implemented in BIND 9 . -directory - The working directory of the server. Any non- -absolute pathnames in the configuration file will -be taken as relative to this directory. The default -location for most server output files (e.g. -named.run) is this directory. If a directory is not -specified, the working directory defaults to `.', -the directory from which the server was started. -The directory specified should be an absolute -path. +6.2.12.1 Boolean Options -named-xfer - This option is obsolete. It was used in BIND 8 to -specify the pathname to the named-xfer -program. In BINDv9, no separate named-xfer -program is needed; its functionality is built into -the name server. + If yes , then the AA bit is always set on NXDOMAIN + responses, even if the server is not actually + auth-nxdomain authoritative. The default is no ; this is a change + from BIND 8. If you are using very old DNS software, + you may need to set it to yes . + This option was used in BIND 8 to enable checking for + deallocate-on-exit memory leaks on exit. BIND 9 ignores the option and + always performs the checks. + If yes , then the server treats all zones as if they + are doing zone transfers across a dial on demand dialup + link, which can be brought up by traffic originating + from this server. This has different effects according + to zone type and concentrates the zone maintenance so + that it all happens in a short interval, once every + heartbeat-interval and hopefully during the one call. + It also suppresses some of the normal zone maintenance + traffic. The default is no . -tkey-domain - The domain appended to the names of all shared -keys generated with TKEY. When a client requests -a TKEY exchange, it may or may not specify the -desired name for the key. If present, the name of -the shared key will be "client specified part" + -"tkey-domain". Otherwise, the name of the shared -key will be "random hex digits" + "tkey-domain". In -most cases, the domainname should be the -server's domain name. + The dialup option may also be specified in the zone + statement, in which case it overrides the options + dialup dialup statement. -tkey-dhkey - The Diffie-Hellman key used by the server to -generate shared keys with clients using the -Diffie-Hellman mode of TKEY. The server must be -able to load the public and private keys from files -in the working directory. In most cases, the -keyname should be the server's host name. + If the zone is a master then the server will send out a + NOTIFY request to all the slaves. This will trigger the + zone serial number check in the slave (providing it + supports NOTIFY) allowing the slave to verify the zone + while the connection is active. -dump-file - The pathname of the file the server dumps the -database to when it receives SIGINT signal (ndc -dumpdb). If not specified, the default is -named_dump.db. Not yet implemented in BINDv9. + If the zone is a slave or stub then the server will + suppress the regular "zone up to date" queries and only + perform them when the + heartbeat-interval expires. Not yet implemented in + BIND 9. + In BIND 8, this option was used to enable simulating + fake-iquery the obsolete DNS query type IQUERY. BIND 9 never does + IQUERY simulation. + (Information present outside of the authoritative nodes + in the zone is called glue information). If yes (the + default), the server will fetch glue resource records + it doesn't have when constructing the additional data + fetch-glue section of a response. fetch-glue no can be used in + conjunction with recursion no to prevent the server's + cache from growing or becoming corrupted (at the cost + of requiring more work from the client). Not yet + implemented in BIND 9. + This option was incorrectly implemented in BIND 8, and + has-old-clients is ignored by BIND 9. To achieve the intended effect of + has-old-clients yes , specify the two separate options + auth-nxdomain yes and rfc2308-type1 no instead. + If yes , then statistics are kept for every host that + host-statistics the nameserver interacts with. The default is no . + Note: turning on host-statistics can consume huge + amounts of memory. Not yet implemented in BIND 9. + This option is obsolete . It was used in BIND 8 to + determine whether a transaction log was kept for + maintain-ixfr-base Incremental Zone Transfer. BIND 9 maintains a + transaction log whenever possible. If you need to + disable outgoing incremental zone transfers, use + provide-ixfr no . + This option was used in BIND 8 to allow a domain name + to allow multiple CNAME records in violation of the DNS + standards. BIND 9 currently does not check for multiple + multiple-cnames CNAMEs in zone data loaded from master files, but such + checks may be introduced in a later release. BIND 9 + always strictly enforces the CNAME rules in dynamic + updates. + If yes (the default), DNS NOTIFY messages are sent when + a zone the server is authoritative for changes. See + Notify , for more information. The notify option may + notify also be specified in the zone statement, in which case + it overrides the options notify statement. It would + only be necessary to turn off this option if it caused + slaves to crash . + If yes , and a DNS query requests recursion, then the + server will attempt to do all the work required to + recursion answer the query. If recursion is not on, the server + will return a referral to the client if it doesn't know + the answer. The default is yes . See also fetch-glue + above. + Setting this to yes will cause the server to send NS + rfc2308-type1 records along with the SOA record for negative answers. + The default is no . Not yet implemented in BIND 9 . -memstatistics-file - The pathname of the file the server writes -memory usage statistics to on exit. If not -specified, the default is named.memstats. Not yet -implemented in BINDv9. + use-id-pool This option is obsolete . BIND 9 always allocates query + IDs from a pool. + This option was used in BIND 8 to make the server treat + " \r " characters the same way as " " or " \t + treat-cr-as-space ", to facilitate loading of zone files on a UNIX system + that were generated on an NT or DOS machine. In BIND 9, + both UNIX " \n " and NT/DOS " \r\n " newlines are + always accepted, and the option is ignored. -pid-file - The pathname of the file the server writes its -process ID in. If not specified, the default is -operating system dependent, but is usually -/var/run/named.pid or /etc/named.pid. The pid-file is -used by programs that want to send signals to the -running nameserver. +6.2.12.2 Forwarding -statistics-file - The pathname of the file the server appends -statistics to. If not specified, the default is -named.stats. Not yet implemented in BINDv9. - - -5.2.12.1 Boolean Options - - - -auth-nxdomain - If yes, then the AA bit is always set on -NXDOMAIN responses, even if the server is -not actually authoritative. The default is no; -this is a change from BIND 8. If you are using -very old DNS software, you may need to set it -to yes. - -deallocate-on-exit - This option was used in BIND 8 to enable -checking for memory leaks on exit. BINDv9 -ignores the option and always performs the -checks. - -dialup - If yes, then the server treats all zones as if they -are doing zone transfers across a dial on -demand dialup link, which can be brought up -by traffic originating from this server. This has -different effects according to zone type and -concentrates the zone maintenance so that it all -happens in a short interval, once every -heartbeat-interval and hopefully during -the one call. It also suppresses some of the -normal zone maintenance traffic. The default -is no. - -The dialup option may also be specified in -the zone statement, in which case it overrides -the options dialup statement. - -If the zone is a master then the server will send -out a NOTIFY request to all the slaves. This -will trigger the zone serial number check in the -slave (providing it supports NOTIFY) -allowing the slave to verify the zone while the -connection is active. - -If the zone is a slave or stub then the server -will suppress the regular "zone up to date" -queries and only perform them when the -heartbeat-interval expires. Not yet -implemented in BINDv9. - -fake-iquery - In BIND 8, this option was used to enable -simulating the obsolete DNS query type -IQUERY. BINDv9 never does IQUERY -simulation. - -fetch-glue - (Information present outside of the -authoritative nodes in the zone is called glue -information). If yes (the default), the server -will fetch glue resource records it doesn't have -when constructing the additional data section -of a response. fetch-glue no can be used in -conjunction with recursion no to prevent the -server's cache from growing or becoming -corrupted (at the cost of requiring more work -from the client). Not yet implemented in -BINDv9. - -has-old-clients - This option was incorrectly implemented in -BIND 8, and is ignored by BINDv9. To -achieve the intended effect of -has-old-clients yes, specify the two -separate options auth-nxdomain yes and -rfc2308-type1 no instead. - -host-statistics - If yes, then statistics are kept for every host -that the nameserver interacts with. The default -is no. Note: turning on host-statistics can -consume huge amounts of memory. Not yet -implemented in BINDv9. - -maintain-ixfr-base - This option is obsolete. It was used in BIND 8 -to determine whether a transaction log was -kept for Incremental Zone Transfer. BINDv9 -maintains a transaction log whenever possible. -If you need to disable outgoing incremental -zone transfers, use provide-ixfr no. - -multiple-cnames - This option was used in BIND 8 to allow a -domain name to allow multiple CNAME -records in violation of the DNS standards. -BINDv9 currently does not check for multiple -CNAMEs in zone data loaded from master -files, but such checks may be introduced in a -later release. BINDv9 always strictly enforces -the CNAME rules in dynamic updates. - -notify - If yes (the default), DNS NOTIFY messages -are sent when a zone the server is authoritative -for changes. See Section 3.3, "Notify", on -page 10, for more information. The notify -option may also be specified in the zone -statement, in which case it overrides the -options notify statement. It would only be -necessary to turn off this option if it caused -slaves to crash. - -recursion - If yes, and a DNS query requests recursion, -then the server will attempt to do all the work -required to answer the query. If recursion is -not on, the server will return a referral to the -client if it doesn't know the answer. The -default is yes. See also fetch-glue above. - -rfc2308-type1 - Setting this to yes will cause the server to send -NS records along The default is no. Not yet -implemented in BINDv9. - -use-id-pool - This option is obsolete. BINDv9 always -allocates query IDs from a pool. - -treat-cr-as-space - This option was used in BIND 8 to make the -server treat "\r" characters the same way as - " " or "\t", to facilitate loading of -zone files on a UNIX system that were -generated on an NT or DOS machine. In -BINDv9, both UNIX "\n" and NT/DOS -"\r\n" newlines are always accepted, and the -option is ignored. - - -5.2.12.2 Forwarding - -The forwarding facility can be used to create a large site-wide cache on a -few servers, reducing traffic over links to external nameservers. It can also -be used to allow queries by servers that do not have direct access to the -Internet, but wish to look up exterior names anyway. Forwarding occurs -only on those queries for which the server is not authoritative and does not +The forwarding facility can be used to create a large site-wide cache on a +few servers, reducing traffic over links to external nameservers. It can +also be used to allow queries by servers that do not have direct access to +the Internet, but wish to look up exterior names anyway. Forwarding occurs +only on those queries for which the server is not authoritative and does not have the answer in its cache. -forward - This option is only meaningful if the forwarders list is -not empty. A value of first, the default, causes the server -to query the forwarders first, and if that doesn't answer -the question the server will then look for the answer -itself. If only is specified, the server will only query the -forwarders. + This option is only meaningful if the forwarders list is not + empty. A value of first , the default, causes the server to + forward query the forwarders first, and if that doesn't answer the + question the server will then look for the answer itself. If + only is specified, the server will only query the forwarders. -forwarders - Specifies the IP addresses to be used for forwarding. -The default is the empty list (no forwarding). + forwarders Specifies the IP addresses to be used for forwarding. The + default is the empty list (no forwarding). +Forwarding can also be configured on a per-domain basis, allowing for the +global forwarding options to be overridden in a variety of ways. You can set +particular domains to use different forwarders, or have a different forward +only/first behavior, or not forward at all. See zone Statement Grammar for +more information. -Forwarding can also be configured on a per-domain basis, allowing for -the global forwarding options to be overridden in a variety of ways. You -can set particular domains to use different forwarders, or have different -forward only/first behavior, or not forward at all. See "zone -Statement Grammar" on page 57 for more information. +6.2.12.3 Name Checking -5.2.12.3 Name Checking - -The server can check domain names based upon their expected client -contexts. For example, a domain name used as a hostname can be checked -for compliance with the RFCs defining valid hostnames. +The server can check domain names based upon their expected client contexts. +For example, a domain name used as a hostname can be checked for compliance +with the RFCs defining valid hostnames. Three checking methods are available: -ignore - No checking is done. + ignore No checking is done. -warn - Names are checked against their expected client contexts. -Invalid names are logged, but processing continues -normally. + warn Names are checked against their expected client contexts. Invalid + names are logged, but processing continues normally. -fail - Names are checked against their expected client contexts. -Invalid names are logged, and the offending data is -rejected. + fail Names are checked against their expected client contexts. Invalid + names are logged, and the offending data is rejected. - -The server can check names in three areas: master zone files, slave zone -files, and in responses to queries the server has initiated. If check-names -response fail has been specified, and answering the client's question -would require sending an invalid name to the client, the server will send a +The server can check names in three areas: master zone files, slave zone +files, and in responses to queries the server has initiated. If check-names +response fail has been specified, and answering the client's question would +require sending an invalid name to the client, the server will send a REFUSED response code to the client. The defaults are: @@ -2291,76 +2205,64 @@ The defaults are: check-names slave warn; check-names response ignore; -check-names may also be specified in the zone statement, in which case -it overrides the options check-names statement. When used in a zone -statement, the area is not specified because it can be deduced from the -zone type. +check-names may also be specified in the zone statement, in which case it +overrides the options check-names statement. When used in a zone statement, +the area is not specified because it can be deduced from the zone type. -Name checking is not yet implemented in BINDv9. +Name checking is not yet implemented in BIND 9. -5.2.12.4 Access Control +6.2.12.4 Access Control -Access to the server can be restricted based on the IP address of the -requesting system. See "Address Match Lists" on page 28 for details on -how to specify IP address lists. +Access to the server can be restricted based on the IP address of the +requesting system. See Address Match Lists for details on how to specify IP +address lists. -allow-query - Specifies which hosts are allowed to ask -ordinary questions. allow-query may also be -specified in the zone statement, in which case it -overrides the options allow-query statement. -If not specified, the default is to allow queries -from all hosts. + Specifies which hosts are allowed to ask ordinary + questions. allow-query may also be specified in the zone + allow-query statement, in which case it overrides the options + allow-query statement. If not specified, the default is to + allow queries from all hosts. + Specifies which hosts are allowed to make recursive + allow-recursion queries through this server. If not specified, the default + is to allow recursive queries from all hosts. + Specifies which hosts are allowed to receive zone + transfers from the server. allow-transfer may also be + allow-transfer specified in the zone statement, in which case it + overrides the options allow-transfer statement. If not + specified, the default is to allow transfers from all + hosts. + Specifies a list of addresses that the server will not + blackhole accept queries from or use to resolve a query. Queries + from these addresses will not be responded to. The default + is none . Not yet implemented in BIND 9. -allow-recursion - Specifies which hosts are allowed to make -recursive queries through this server. If not -specified, the default is to allow recursive queries -from all hosts. +6.2.12.5 Interfaces -allow-transfer - Specifies which hosts are allowed to receive -zone transfers from the server. allow-transfer -may also be specified in the zone statement, in -which case it overrides the options allow- -transfer statement. If not specified, the default -is to allow transfers from all hosts. - -blackhole - Specifies a list of addresses that the server will -not accept queries from or use to resolve a query. -Queries from these addresses will not be -responded to. The default is none. Not yet -implemented in BINDv9. - - -5.2.12.5 Interfaces - -The interfaces and ports that the server will answer queries from may be -specified using the listen-on option. listen-on takes an optional port, -and an address_match_list. The server will listen on all interfaces allowed -by the address match list. If a port is not specified, port 53 will be used. +The interfaces and ports that the server will answer queries from may be +specified using the listen-on option. listen-on takes an optional port, and +an address_match_list . The server will listen on all interfaces allowed by +the address match list. If a port is not specified, port 53 will be used. Multiple listen-on statements are allowed. For example, listen-on { 5.6.7.8; }; listen-on port 1234 { !1.2.3.4; 1.2/16; }; -will enable the nameserver on port 53 for the IP address 5.6.7.8, and on +will enable the nameserver on port 53 for the IP address 5.6.7.8, and on port 1234 of an address on the machine in net 1.2 that is not 1.2.3.4. -If no listen-on is specified, the server will listen on port 53 on all +If no listen-on is specified, the server will listen on port 53 on all interfaces. -The listen-on-v6 option is used to specify the ports on which the server +The listen-on-v6 option is used to specify the ports on which the server will listen for incoming queries sent using IPv6. -The server does not bind a separate socket to each IPv6 interface address -as it does for IPv4. Instead, it always listens on the IPv6 wildcard address. -Therefore, the only values allowed for the address_match_list argument -to the listen-on-v6 statement are "{ any; }" and "{ none; }". +The server does not bind a separate socket to each IPv6 interface address as +it does for IPv4. Instead, it always listens on the IPv6 wildcard address. +Therefore, the only values allowed for the address_match_list argument to +the listen-on-v6 statement are " { any; } " and " { none; } ". Multiple listen-on-v6 options can be used to listen on multiple ports: @@ -2371,277 +2273,204 @@ To make the server not listen on any IPv6 address, use listen-on-v6 { none; }; -If no listen-on-v6 statement is specified, the server will listen on port -53 on the IPv6 wildcard address. +If no listen-on-v6 statement is specified, the server will listen on port 53 +on the IPv6 wildcard address. -5.2.12.6 Query Address +6.2.12.6 Query Address -If the server doesn't know the answer to a question, it will query other -nameservers. query-source specifies the address and port used for such -queries. For queries sent over IPv6, there is a separate query-source-v6 -option. If address is * or is omitted, a wildcard IP address (INADDR_ANY) -will be used. If port is * or is omitted, a random unprivileged port will be +If the server doesn't know the answer to a question, it will query other +nameservers. query-source specifies the address and port used for such +queries. For queries sent over IPv6, there is a separate query-source-v6 +option. If address is * or is omitted, a wildcard IP address ( INADDR_ANY ) +will be used. If port is * or is omitted, a random unprivileged port will be used. The defaults are query-source address * port *; query-source-v6 address * port * -Note: query-source currently applies only to UDP queries; TCP queries -always use a wildcard IP address and a random unprivileged port. +Note: query-source currently applies only to UDP queries; TCP queries always +use a wildcard IP address and a random unprivileged port. -5.2.12.7 Zone Transfers +6.2.12.7 Zone Transfers -BIND has mechanisms in place to facilitate zone transfers and set limits -on the amount of load that transfers place on the system. The following -options apply to zone transfers. +BIND has mechanisms in place to facilitate zone transfers and set limits on +the amount of load that transfers place on the system. The following options +apply to zone transfers. -also-notify - Defines a global list of IP addresses that -are also sent NOTIFY messages whenever -a fresh copy of the zone is loaded. This -helps to ensure that copies of the zones -will quickly converge on stealth servers. If -an also-notify list is given in a zone -statement, it will override the options -also-notify statement. When a zone -notify statement is set to no, the IP -addresses in the global also-notify list -will not be sent NOTIFY messages for that -zone. The default is the empty list (no -global notification list). + Defines a global list of IP addresses that are also + sent NOTIFY messages whenever a fresh copy of the + zone is loaded. This helps to ensure that copies of + the zones will quickly converge on stealth servers. + also-notify If an also-notify list is given in a zone statement, + it will override the options also-notify statement. + When a zone notify statement is set to no , the IP + addresses in the global also-notify list will not be + sent NOTIFY messages for that zone. The default is + the empty list (no global notification list). + Inbound zone transfers running longer than this many + max-transfer-time-in minutes will be terminated. The default is 120 + minutes (2 hours). + Inbound zone transfers making no progress in this + max-transfer-idle-in many minutes will be terminated. The default is 60 + minutes (1 hour). + Outbound zone transfers running longer than this + max-transfer-time-out many minutes will be terminated. The default is 120 + minutes (2 hours). + Outbound zone transfers making no progress in this + many minutes will be terminated. The default is 60 + max-transfer-idle-out minutes -max-transfer-time-in - Inbound zone transfers running longer -than this many minutes will be terminated. -The default is 120 minutes (2 hours). + (1 hour). + Slave servers will periodically query master servers + to find out if zone serial numbers have changed. + Each such query uses a minute amount of the slave + server's network bandwidth, but more importantly + each query uses a small amount of memory in the + slave server while waiting for the master server to + respond. The serial-queries option sets the maximum + number of concurrent serial-number queries allowed + to be outstanding at any given time. The default is + serial-queries 4. Note: If a server loads a large (tens or hundreds + of thousands) number of slave zones, then this limit + should be raised to the high hundreds or low + thousands, otherwise the slave server may never + actually become aware of zone changes in the master + servers. Beware, though, that setting this limit + arbitrarily high can spend a considerable amount of + your slave server's network, CPU, and memory + resources. As with all tunable limits, this one + should be changed gently and monitored for its + effects. Not yet implemented in BIND 9. + The server supports two zone transfer methods. + one-answer uses one DNS message per resource record + transferred. many-answers packs as many resource + records as possible into a message. many-answers is + transfer-format more efficient, but is only known to be understood + by BIND 9, BIND 8.x and patched versions of + BIND 4.9.5. The default is many-answers . + transfer-format may be overridden on a per-server + basis by using the server statement. + The maximum number of inbound zone transfers that + can be running concurrently. The default value is 10 + transfers-in . Increasing transfers-in may speed up the + convergence of slave zones, but it also may increase + the load on the local system. + The maximum number of outbound zone transfers that + transfers-out can be running concurrently. Zone transfer requests + in excess of the limit will be refused. The default + value is 10 . + The maximum number of inbound zone transfers that + can be concurrently transferring from a given remote + nameserver. The default value is 2 . Increasing + transfers-per-ns transfers-per-ns may speed up the convergence of + slave zones, but it also may increase the load on + the remote nameserver. transfers-per-ns may be + overridden on a per-server basis by using the + transfers phrase of the server statement. + transfer-source determines which local address will + be bound to IPv4 TCP connections used to fetch zones + transferred inbound by the server. If not set, it + defaults to a system controlled value which will + usually be the address of the interface "closest to" + the remote end. This address must appear in the + transfer-source remote end's allow-transfer option for the zone + being transferred, if one is specified. This + statement sets the transfer-source for all zones, + but can be overridden on a per-zone basis by + including a + transfer-source statement within the zone block in + the configuration file. -max-transfer-idle-in - Inbound zone transfers making no -progress in this many minutes will be -terminated. The default is 60 minutes (1 -hour). + transfer-source-v6 The same as transfer-source , except zone transfers + are performed using IPv6. -max-transfer-time-out - Outbound zone transfers running longer -than this many minutes will be terminated. -The default is 120 minutes (2 hours). +6.2.12.8 Resource Limits -max-transfer-idle-out - Outbound zone transfers making no -progress in this many minutes will be -terminated. The default is 60 minutes +The server's usage of many system resources can be limited. Some operating +systems don't support some of the limits. On such systems, a warning will be +issued if the unsupported limit is used. Some operating systems don't +support limiting resources. -(1 hour). - -serial-queries - Slave servers will periodically query -master servers to find out if zone serial -numbers have changed. Each such query -uses a minute amount of the slave server's -network bandwidth, but more importantly -each query uses a small amount of -memory in the slave server while waiting -for the master server to respond. The -serial-queries option sets the -maximum number of concurrent serial- -number queries allowed to be outstanding -at any given time. The default is 4. Note: If -a server loads a large (tens or hundreds of -thousands) number of slave zones, then -this limit should be raised to the high -hundreds or low thousands, otherwise the -slave server may never actually become -aware of zone changes in the master -servers. Beware, though, that setting this -limit arbitrarily high can spend a -considerable amount of your slave server's -network, CPU, and memory resources. As -with all tunable limits, this one should be -changed gently and monitored for its -effects. Not yet implemented in BINDv9. - -transfer-format - The server supports two zone transfer -methods. one-answer uses one DNS -message per resource record transferred. -many-answers packs as many resource -records as possible into a message. many- -answers is more efficient, but is only -known to be understood by BINDv9, -BIND 8.x and patched versions of BIND -4.9.5. The default is one-answer. -transfer-format may be overridden on a -per-server basis by using the server -statement. - -transfers-in - The maximum number of inbound zone -transfers that can be running concurrently. -The default value is 10. Increasing -transfers-in may speed up the -convergence of slave zones, but it also may -increase the load on the local system. - -transfers-out - The maximum number of outbound zone -transfers that can be running concurrently. -Zone transfer requests in excess of the -limit will be refused. The default value is -10. - -transfers-per-ns - The maximum number of inbound zone -transfers that can be concurrently -transferring from a given remote -nameserver. The default value is 2. -Increasing transfers-per-ns may speed -up the convergence of slave zones, but it -also may increase the load on the remote -nameserver. transfers-per-ns may be -overridden on a per-server basis by using -the transfers phrase of the server -statement. - -transfer-source - transfer-source determines which local -address will be bound to IPv4 TCP -connections used to fetch zones -transferred inbound by the server. If not -set, it defaults to a system controlled value -which will usually be the address of the -interface "closest to" the remote end. This -address must appear in the remote end's -allow-transfer option for the zone being -transferred, if one is specified. This -statement sets the transfer-source for -all zones, but can be overridden on a per- -zone basis by including a -transfer-source statement within the -zone block in the configuration file. - -transfer-source-v6 - Like transfer-source, but for zone -transfers performed using IPv6. - - -5.2.12.8 Resource Limits - -The server's usage of many system resources can be limited. Some -operating systems don't support some of the limits. On such systems, a -warning will be issued if the unsupported limit is used. Some operating -systems don't support limiting resources. - -Scaled values are allowed when specifying resource limits. For example, -1G can be used instead of 1073741824 to specify a limit of one gigabyte. -unlimited requests unlimited use, or the maximum available amount. -default uses the limit that was in force when the server was started. See -the description of size_spec in "Configuration File Grammar" on -page 30 for more details. +Scaled values are allowed when specifying resource limits. For example, 1G +can be used instead of 1073741824 to specify a limit of one gigabyte. +unlimited requests unlimited use, or the maximum available amount. default +uses the limit that was in force when the server was started. See the +description of size_spec in Configuration File Elements for more details. -coresize - The maximum size of a core dump. The -default is default. Not yet implemented in -BINDv9. + coresize The maximum size of a core dump. The default is default + . Not yet implemented in BIND 9. -datasize - The maximum amount of data memory the -server may use. The default is default. Not -yet implemented in BINDv9. + datasize The maximum amount of data memory the server may use. + The default is default . Not yet implemented in BIND 9. + The maximum number of files the server may have open + concurrently. The default is unlimited . Note: on some + operating systems the server cannot set an unlimited + value and cannot determine the maximum number of open + files files the kernel can support. On such systems, choosing + unlimited will cause the server to use the larger of the + rlim_max for RLIMIT_NOFILE and the value returned by + sysconf(_SC_OPEN_MAX) . If the actual kernel limit is + larger than this value, use limit files to specify the + limit explicitly. Not yet implemented in BIND 9. + The max-ixfr-log-size will be used in a future release + max-ixfr-log-size of the server to limit the size of the transaction log + kept for Incremental Zone Transfer. Not yet implemented + in BIND 9. + The maximum number of simultaneous recursive lookups the + recursive-clients server will perform on behalf of clients. The default is + 100 . -files - The maximum number of files the server may -have open concurrently. The default is -unlimited. Note: on some operating systems -the server cannot set an unlimited value and -cannot determine the maximum number of -open files the kernel can support. On such -systems, choosing unlimited will cause the -server to use the larger of the rlim_max for -RLIMIT_NOFILE and the value returned by -sysconf(_SC_OPEN_MAX). If the actual kernel -limit is larger than this value, use limit files -to specify the limit explicitly. Not yet -implemented in BINDv9. + stacksize The maximum amount of stack memory the server may use. + The default is default . Not yet implemented in BIND 9. + The maximum number of simultaneous client TCP + tcp-clients connections that the server will accept. The default is + 100 . -max-ixfr-log-size - The max-ixfr-log-size will be used in a -future release of the server to limit the size of -the transaction log kept for Incremental Zone -Transfer. Not yet implemented in BINDv9. +Resource limits are not yet implemented in BIND 9. -recursive-clients - The maximum number of simultaneous -recursive lookup the server will perform on -behalf of clients. The default is 100. - -stacksize - The maximum amount of stack memory the -server may use. The default is default. Not -yet implemented in BINDv9. - -tcp-clients - The maximum number of simultaneous client -TCP connections that the server will accept. -The default is 100. - - -Resource limits are not yet implemented in BINDv9. - -5.2.12.9 Periodic Task Intervals +6.2.12.9 Periodic Task Intervals -cleaning-interval - The server will remove expired resource -records from the cache every cleaning- -interval minutes. The default is 60 -minutes. If set to 0, no periodic cleaning -will occur. + The server will remove expired resource records from + cleaning-interval the cache every cleaning-interval minutes. The default + is 60 minutes. If set to 0 , no periodic cleaning will + occur. + The server will perform zone maintenance tasks for all + zones marked dialup yes whenever this interval + heartbeat-interval expires. The default is 60 minutes. Reasonable values + are up to 1 day (1440 minutes). If set to 0 , no zone + maintenance for these zones will occur. Not yet + implemented in BIND 9. + The server will scan the network interface list every + interface-interval minutes. The default is 60 minutes. + If set to 0 , interface scanning will only occur when + interface-interval the configuration file is loaded. After the scan, + listeners will be started on any new interfaces + (provided they are allowed by the listen-on + configuration). Listeners on interfaces that have gone + away will be cleaned up. + Nameserver statistics will be logged every + statistics-interval statistics-interval minutes. The default is 60 . If + set to 0 , no statistics will be logged. Not yet + implemented in BIND 9. -heartbeat-interval - The server will perform zone maintenance -tasks for all zones marked dialup yes -whenever this interval expires. The default is -60 minutes. Reasonable values are up to 1 -day (1440 minutes). If set to 0, no zone -maintenance for these zones will occur. Not -yet implemented in BINDv9. +6.2.12.10 Topology -interface-interval - The server will scan the network interface -list every interface-interval minutes. -The default is 60 minutes. If set to 0, -interface scanning will only occur when the -configuration file is loaded. After the scan, -listeners will be started on any new -interfaces (provided they are allowed by the -listen-on configuration). Listeners on -interfaces that have gone away will be -cleaned up. - -statistics-interval - Nameserver statistics will be logged every -statistics-interval minutes. The default -is 60. If set to 0, no statistics will be logged. -Not yet implemented in BINDv9. - - -5.2.12.10 Topology - -All other things being equal, when the server chooses a nameserver to -query from a list of nameservers, it prefers the one that is topologically -closest to itself. The topology statement takes an address_match_list -and interprets it in a special way. Each top-level list element is assigned a -distance. Non-negated elements get a distance based on their position in -the list, where the closer the match is to the start of the list, the shorter the -distance is between it and the server. A negated match will be assigned the -maximum distance from the server. If there is no match, the address will -get a distance which is further than any non-negated list element, and -closer than any negated element. For example, +All other things being equal, when the server chooses a nameserver to query +from a list of nameservers, it prefers the one that is topologically closest +to itself. The topology statement takes an address_match_list and interprets +it in a special way. Each top-level list element is assigned a distance. +Non-negated elements get a distance based on their position in the list, +where the closer the match is to the start of the list, the shorter the +distance is between it and the server. A negated match will be assigned the +maximum distance from the server. If there is no match, the address will get +a distance which is further than any non-negated list element, and closer +than any negated element. For example, topology { 10/8; @@ -2649,132 +2478,124 @@ closer than any negated element. For example, { 1.2/16; 3/8; }; }; -will prefer servers on network 10 the most, followed by hosts on network -1.2.0.0 (netmask 255.255.0.0) and network 3, with the exception of hosts -on network 1.2.3 (netmask 255.255.255.0), which is preferred least of all. +will prefer servers on network 10 the most, followed by hosts on network +1.2.0.0 (netmask 255.255.0.0) and network 3, with the exception of hosts on +network 1.2.3 (netmask 255.255.255.0), which is preferred least of all. The default topology is topology { localhost; localnets; }; -The topology option is not yet implemented in BINDv9. +The topology option is not yet implemented in BIND 9. -5.2.12.11 The sortlist Statement +6.2.12.11 The sortlist Statement -Resource Records (RRs) are the data associated with the names in a -domain name space. The data is maintained in the form of sets of RRs. -The order of RRs in a set is, by default, not significant. Therefore, to -control the sorting of records in a set resource records, or RRset, you must -use the sortlist statement. +Resource Records (RRs) are the data associated with the names in a domain +name space. The data is maintained in the form of sets of RRs. The order of +RRs in a set is, by default, not significant. Therefore, to control the +sorting of records in a set of resource records, or RRset , you must use the +sortlist statement. -RRs are explained more fully in Section 5.3.1, "Types of Resource -Records and When to Use Them", on page 62. Specifications for RRs are -documented in RFC 1035. +RRs are explained more fully in See Types of Resource Records and When to +Use Them . Specifications for RRs are documented in RFC 1035. -When returning multiple RRs the nameserver will normally return them -in Round Robin order, that is, after each request the first RR is put at the -end of the list. The client resolver code should rearrange the RRs as -appropriate, that is, using any addresses on the local net in preference to -other addresses. However, not all resolvers can do this or are correctly -configured. When a client is using a local server the sorting can be -performed in the server, based on the client's address. This only requires +When returning multiple RRs the nameserver will normally return them in +Round Robin order, that is, after each request the first RR is put at the +end of the list. The client resolver code should rearrange the RRs as +appropriate, that is, using any addresses on the local net in preference to +other addresses. However, not all resolvers can do this or are correctly +configured. When a client is using a local server the sorting can be +performed in the server, based on the client's address. This only requires configuring the nameservers, not all the clients. -The sortlist statement (see below) takes an address_match_list and -interprets it even more specifically than the topology statement does (see -"Topology" on page 50). Each top level statement in the sortlist must -itself be an explicit address_match_list with one or two elements. The -first element (which may be an IP address, an IP prefix, an ACL name or a -nested address_match_list) of each top level list is checked against the -source address of the query until a match is found. +The sortlist statement (see below) takes an address_match_list and +interprets it even more specifically than the topology statement does (see +Topology ). Each top level statement in the sortlist must itself be an +explicit address_match_list with one or two elements. The first element +(which may be an IP address, an IP prefix, an ACL name or a nested +address_match_list ) of each top level list is checked against the source +address of the query until a match is found. -Once the source address of the query has been matched, if the top level -statement contains only one element, the actual primitive element that -matched the source address is used to select the address in the response to -move to the beginning of the response. If the statement is a list of two -elements, then the second element is treated like the -address_match_list in a topology statement. Each top level element is -assigned a distance and the address in the response with the minimum +Once the source address of the query has been matched, if the top level +statement contains only one element, the actual primitive element that +matched the source address is used to select the address in the response to +move to the beginning of the response. If the statement is a list of two +elements, then the second element is treated the same as the +address_match_list in a topology statement. Each top level element is +assigned a distance and the address in the response with the minimum distance is moved to the beginning of the response. -In the following example, any queries received from any of the addresses -of the host itself will get responses preferring addresses on any of the -locally connected networks. Next most preferred are addresses on the +In the following example, any queries received from any of the addresses of +the host itself will get responses preferring addresses on any of the +locally connected networks. Next most preferred are addresses on the 192.168.1/24 network, and after that either the 192.168.2/24 or -192.168.3/24 network with no preference shown between these two -networks. Queries received from a host on the 192.168.1/24 network will -prefer other addresses on that network to the 192.168.2/24 and -192.168.3/24 networks. Queries received from a host on the 192.168.4/24 -or the 192.168.5/24 network will only prefer other addresses on their -directly connected networks. +192.168.3/24 network with no preference shown between these two networks. +Queries received from a host on the 192.168.1/24 network will prefer other +addresses on that network to the 192.168.2/24 and +192.168.3/24 networks. Queries received from a host on the 192.168.4/24 or +the 192.168.5/24 network will only prefer other addresses on their directly +connected networks. sortlist { - { localhost; // IF the local host - { localnets; // THEN first fit on the - 192.168.1/24; // following nets + { localhost; // IF the local host + { localnets; // THEN first fit on the + 192.168.1/24; // following nets { 192,168.2/24; 192.168.3/24; }; }; }; - { 192.168.1/24; // IF on class C 192.168.1 - { 192.168.1/24; // THEN use .1, or .2 or .3 + { 192.168.1/24; // IF on class C 192.168.1 + { 192.168.1/24; // THEN use .1, or .2 or .3 { 192.168.2/24; 192.168.3/24; }; }; }; - { 192.168.2/24; // IF on class C 192.168.2 - { 192.168.2/24; // THEN use .2, or .1 or .3 + { 192.168.2/24; // IF on class C 192.168.2 + { 192.168.2/24; // THEN use .2, or .1 or .3 { 192.168.1/24; 192.168.3/24; }; }; }; - { 192.168.3/24; // IF on class C 192.168.3 - { 192.168.3/24; // THEN use .3, or .1 or .2 + { 192.168.3/24; // IF on class C 192.168.3 + { 192.168.3/24; // THEN use .3, or .1 or .2 { 192.168.1/24; 192.168.2/24; }; }; }; { { 192.168.4/24; 192.168.5/24; }; - // if .4 or .5, prefer that net + // if .4 or .5, prefer that net }; }; -The following example will give reasonable behavior for the local host -and hosts on directly connected networks. It is similar to the behavior of -the address sort in BIND 8.x. Responses sent to queries from the local -host will favor any of the directly connected networks. Responses sent to -queries from any other hosts on a directly connected network will prefer -addresses on that same network. Responses to other queries will not be -sorted. +The following example will give reasonable behavior for the local host and +hosts on directly connected networks. It is similar to the behavior of the +address sort in BIND 8.x. Responses sent to queries from the local host will +favor any of the directly connected networks. Responses sent to queries from +any other hosts on a directly connected network will prefer addresses on +that same network. Responses to other queries will not be sorted. sortlist { { localhost; localnets; }; { localnets; }; }; -The sortlist option is not yet implemented in BINDv9. +The sortlist option is not yet implemented in BIND 9. -5.2.12.12 RRset Ordering +6.2.12.12 RRset Ordering -When multiple records are returned in an answer it may be useful to -configure the order of the records placed into the response. For example, -the records for a zone might be configured always to be returned in the -order they are defined in the zone file. Or perhaps a random shuffle of the -records as they are returned is wanted. The rrset-order statement -permits configuration of the ordering made of the records in a multiple -record response. The default, if no ordering is defined, is a cyclic ordering +When multiple records are returned in an answer it may be useful to +configure the order of the records placed into the response. For example, +the records for a zone might be configured always to be returned in the +order they are defined in the zone file. Or perhaps a random shuffle of the +records as they are returned is wanted. The rrset-order statement permits +configuration of the ordering made of the records in a multiple record +response. The default, if no ordering is defined, is a cyclic ordering (round robin). An order_spec is defined as follows: -[ class class_name ][ type type_name ][ name "domain_name"] - order ordering +[ class class_name ][ type type_name ][ name "domain_name"] + order ordering -If no class is specified, the default is ANY. If no type is specified, the -default is ANY. If no name is specified, the default is `*'. +If no class is specified, the default is ANY . If no type is specified, the +default is ANY . If no name is specified, the default is " * ". The legal values for ordering are: -fixed - Records are returned in the order they are defined in the -zone file. - -random - Records are returned in some random order. - -cyclic - Records are returned in a round-robin order. - + fixed Records are returned in the order they are defined in the zone + file. + random Records are returned in some random order. + cyclic Records are returned in a round-robin order. For example: @@ -2783,202 +2604,199 @@ For example: order cyclic; }; -will cause any responses for type A records in class IN that have -"host.example.com" as a suffix, to always be returned in random order. -All other records are returned in cyclic order. +will cause any responses for type A records in class IN that have " +host.example.com " as a suffix, to always be returned in random order. All +other records are returned in cyclic order. -If multiple rrset-order statements appear, they are not combined-the -last one applies. +If multiple rrset-order statements appear, they are not combined--the last +one applies. If no rrset-order statement is specified, then a default one of: - rrset-order { class ANY type ANY name "*"; order cyclic ; -}; + rrset-order { class ANY type ANY name "*"; order cyclic ; + }; is used. -The rrset-order statement is not yet implemented in BINDv9. +The rrset-order statement is not yet implemented in BIND 9. -5.2.12.13 Tuning +6.2.12.13 Tuning -lame-ttl - Sets the number of seconds to cache a lame server -indication. 0 disables caching. (This is NOT -recommended.) Default is 600 (10 minutes). -Maximum value is 1800 (30 minutes). Not yet -implemented in BINDv9. + Sets the number of seconds to cache a lame server + indication. 0 disables caching. (This is NOT + lame-ttl recommended.) Default is 600 (10 minutes). Maximum + value is 1800 (30 minutes). Not yet implemented in + BIND 9. + To reduce network traffic and increase performance + the server stores negative answers. max-ncache-ttl + is used to set a maximum retention time for these + max-ncache-ttl answers in the server in seconds. The default + max-ncache-ttl is 10800 seconds (3 hours). + max-ncache-ttl cannot exceed 7 days and will be + silently truncated to 7 days if set to a greater + value. + max-cache-ttl sets the maximum time for which the + max-cache-ttl server will cache ordinary (positive) answers. The + default is one week (7 days). + The minimum number of root servers that is required + min-roots for a request for the root servers to be accepted. + Default is 2 . Not yet implemented in BIND 9. + Specifies the number of days into the future when + DNSSEC signatures automatically generated as a + result of dynamic updates (see Dynamic Update ) will + sig-validity-interval expire. The default is 30 days. The signature + inception time is unconditionally set to one hour + before the current time to allow for a limited + amount of clock skew. -max-ncache-ttl - To reduce network traffic and increase -performance the server stores negative answers. -max-ncache-ttl is used to set a maximum -retention time for these answers in the server in -seconds. The default -max-ncache-ttl is 10800 seconds (3 hours). -max-ncache-ttl cannot exceed 7 days and will be -silently truncated to 7 days if set to a greater value. +6.2.12.14 Deprecated Features -max-cache-ttl - max-cache-ttl sets the maximum time for which -the server will cache ordinary (positive) answers. -The default is one week (7 days). +use-ixfr is deprecated in BIND 9. If you need to disable IXFR to a +particular server or servers see the information on the provide-ixfr option +in server Statement Definition and Usage . See also the description of IXFR +in the section Incremental Zone Transfers (IXFR) . -min-roots - The minimum number of root servers that is -required for a request for the root servers to be -accepted. Default is 2. Not yet implemented in -BINDv9. - -sig-validity- -interval - Specifies the number of days into the future when -DNSSEC signatures automatically generated as a -result of dynamic updates (see Section 4.1, -"Dynamic Update", on page 13 ) will expire. The -default is 30 days. The signature inception time is -unconditionally set to one hour before the current -time to allow for a limited amount of clock skew. - - -5.2.12.14 Deprecated Features - -use-ixfr is deprecated in BINDv9. If you need to disable IXFR to a -particular server or servers see the information on the provide-ixfr -option in "server Statement Grammar" on page 54. See also the -description of Incremental Transfer (IXFR) in the section Section 4.2, -"Incremental Zone Transfers (IXFR)", on page 13. - -5.2.13 server Statement Grammar +6.2.13 server Statement Grammar server ip_addr { + [ bogus yes_or_no ; ] [ provide-ixfr yes_or_no ; ] [ request-ixfr yes_or_no ; ] [ transfers number ; ] [ transfer-format ( one-answer | many-answers ) ; ] - [ keys { string ; [ string ; [...]] } ; ] -}; + [ keys { string ; [ string ; [...]] } ; ] +}; } -5.2.14 server Statement Definition and Usage +6.2.14 server Statement Definition and Usage -The server statement defines the characteristics to be associated with a remote -nameserver. +The server statement defines the characteristics to be associated with a +remote nameserver. -If you discover that a remote server is giving out bad data, marking it as bogus will -prevent further queries to it. The default value of bogus is no. The bogus clause is -not yet implemented in BINDv9. +If you discover that a remote server is giving out bad data, marking it as +bogus will prevent further queries to it. The default value of bogus is no . +The bogus clause is not yet implemented in BIND 9. -The provide-ixfr clause determines whether the local server, acting as master, will -respond with an incremental zone transfer when the given remote server, a slave, -requests it. If set to yes, incremental transfer will be provided whenever possible. If -set to no, all transfers to the remote server will be nonincremental. If not set, the -value of the provide-ixfr option in the global options block is used as a default. +The provide-ixfr clause determines whether the local server, acting as +master, will respond with an incremental zone transfer when the given remote +server, a slave, requests it. If set to yes , incremental transfer will be +provided whenever possible. If set to no , all transfers to the remote +server will be nonincremental. If not set, the value of the provide-ixfr +option in the global options block is used as a default. -The request-ixfr clause determines whether the local server, acting as a slave, -will request incremental zone transfers from the given remote server, a master. If not -set, the value of the request-ixfr option in the global options block is used as a -default. +The request-ixfr clause determines whether the local server, acting as a +slave, will request incremental zone transfers from the given remote server, +a master. If not set, the value of the request-ixfr option in the global +options block is used as a default. -IXFR requests to servers that do not support IXFR will automatically fall back to -AXFR. Therefore, there is no need to manually list which servers support IXFR and -which ones do not; the global default of yes should always work. The purpose of the -provide-ixfr and request-ixfr clauses is to make it possible to disable the use of -IXFR even when both master and slave claim to support it, for example if one of the -servers is buggy and crashes or corrupts data when IXFR is used. +IXFR requests to servers that do not support IXFR will automatically fall +back to AXFR. Therefore, there is no need to manually list which servers +support IXFR and which ones do not; the global default of yes should always +work. The purpose of the provide-ixfr and request-ixfr clauses is to make it +possible to disable the use of IXFR even when both master and slave claim to +support it, for example if one of the servers is buggy and crashes or +corrupts data when IXFR is used. -The server supports two zone transfer methods. The first, one-answer, uses one -DNS message per resource record transferred. many-answers packs as many -resource records as possible into a message. many-answers is more efficient, but is -only known to be understood by BINDv9, BIND 8.x, and patched versions of BIND -4.9.5. You can specify which method to use for a server with the transfer-format -option. If transfer-format is not specified, the transfer-format specified by the -options statement will be used. +The server supports two zone transfer methods. The first, one-answer , uses +one DNS message per resource record transferred. many-answers packs as many +resource records as possible into a message. many-answers is more efficient, +but is only known to be understood by BIND 9, BIND 8.x, and patched versions +of BIND 4.9.5. You can specify which method to use for a server with the +transfer-format option. If transfer-format is not specified, the +transfer-format specified by the options statement will be used. -transfers is used to limit the number of concurrent inbound zone transfers from -the specified server. If no transfers clause is specified, the limit is set according to -the transfers-per-ns option. +transfers is used to limit the number of concurrent inbound zone transfers +from the specified server. If no transfers clause is specified, the limit is +set according to the transfers-per-ns option. -The keys clause is used to identify a key_id defined by the key statement, to be -used for transaction security when talking to the remote server. The key statement -must come before the server statement that references it. When a request is sent to -the remote server, a request signature will be generated using the key specified here -and appended to the message. A request originating from the remote server is not -required to be signed by this key. +The keys clause is used to identify a key_id defined by the key statement, +to be used for transaction security when talking to the remote server. The +key statement must come before the server statement that references it. When +a request is sent to the remote server, a request signature will be +generated using the key specified here and appended to the message. A +request originating from the remote server is not required to be signed by +this key. -Although the grammar of the keys clause allows for multiple keys, only a single key -per server is currently supported. +Although the grammar of the keys clause allows for multiple keys, only a +single key per server is currently supported. -5.2.15 trusted-keys Statement Grammar +6.2.15 trusted-keys Statement Grammar trusted-keys { string number number number string ; [ string number number number string ; [...]] -}; +}; } -5.2.16 trusted-keys Statement Definition and Usage +6.2.16 trusted-keys Statement Definition and Usage -The trusted-keys statement defines DNSSEC security roots. DNSSEC is -described in Section 4.6, "DNSSEC", on page 19. A security root is defined when -the public key for a non-authoritative zone is known, but cannot be securely -obtained through DNS, either because it is the DNS root zone or its parent zone is -unsigned. Once a key has been configured as a trusted key, it is treated as if it had -been validated and proven secure. The resolver attempts DNSSEC validation on all -DNS data in subdomains of a security root. +The trusted-keys statement defines DNSSEC security roots. See DNSSEC for a +description. A security root is defined when the public key for a +non-authoritative zone is known, but cannot be securely obtained through +DNS, either because it is the DNS root zone or its parent zone is unsigned. +Once a key has been configured as a trusted key, it is treated as if it had +been validated and proven secure. The resolver attempts DNSSEC validation on +all DNS data in subdomains of a security root. -The trusted-keys statement can contain multiple key entries, each consisting of -the key's domain name, flags, protocol, algorithm, and the base-64 representation of -the key data. +The trusted-keys statement can contain multiple key entries, each consisting +of the key's domain name, flags, protocol, algorithm, and the base-64 +representation of the key data. -5.2.17 view Statement Grammar +6.2.17 view Statement Grammar -view view name { + view view name { match_clients { address_match_list } ; [view_option; ...] [zone_statement; ...]] }; -5.2.18 view Statement Definition and Usage +6.2.18 view Statement Definition and Usage -The view statement is a powerful new feature of BINDv9 that lets a name server -answer a DNS query differently depending on who is asking. It is particularly useful -for implementing split DNS setups without having to run multiple servers. +The view statement is a powerful new feature of BIND 9 that lets a name +server answer a DNS query differently depending on who is asking. It is +particularly useful for implementing split DNS setups without having to run +multiple servers. -Each view statement defines a view of the DNS namespace that will be seen by -those clients whose IP addresses match the address_match_list of the view's match- -clients clause. The order of the view statements is significant-a client query will -be resolved in the context of the first view whose match-clients list matches the -client's IP address. +Each view statement defines a view of the DNS namespace that will be seen by +those clients whose IP addresses match the address_match_list of the view's +match-clients clause. The order of the view statements is significant--a +client query will be resolved in the context of the first view whose +match-clients list matches the client's IP address. -Zones defined within a view statement will be only be accessible to clients that -match the view. By defining a zone of the same name in multiple views, different -zone data can be given to different clients, for example, "internal" and "external" -clients in a split DNS setup. +Zones defined within a view statement will be only be accessible to clients +that match the view . By defining a zone of the same name in multiple views, +different zone data can be given to different clients, for example, +"internal" and "external" clients in a split DNS setup. -Many of the options given in the options statement can also be used within a view -statement, and then apply only when resolving queries with that view. When no a -view-specific value is given, the value in the options statement is used as a default. -Also, zone options can have default values specified in the view statement; these -view-specific defaults take precedence over those in the options statement. +Many of the options given in the options statement can also be used within a +view statement, and then apply only when resolving queries with that view. +When no a view-specific value is given, the value in the options statement +is used as a default. Also, zone options can have default values specified +in the view statement; these view-specific defaults take precedence over +those in the options statement. -Views are class specific. If no class is given, class IN is assumed. +Views are class specific. If no class is given, class IN is assumed. -If there are no view statements in the config file, a default view that matches any -client is automatically created in class IN, and any zone statements specified on the -top level of the configuration file are considered to be part of this default view. If -any explicit view statements are present, all zone statements must occur inside view +If there are no view statements in the config file, a default view that +matches any client is automatically created in class IN, and any zone +statements specified on the top level of the configuration file are +considered to be part of this default view. If any explicit view statements +are present, all zone statements must occur inside view statements. + +A zone statement of type hint for the root zone (` . ') does not strictly +define a zone. Therefore, it should not be included in a view statement. + +Here is an example of a typical split DNS setup implemented using view statements. -Here is an example of a typical split DNS setup implemented using view statements. - view "internal" { - // This should match our internal networks. + // This should match our internal networks. match-clients { 10.0.0.0/8; }; - // Provide recursive service to internal clients only. + // Provide recursive service to internal clients only. recursion yes; - // Provide a complete view of the example.com zone - // including addresses of internal hosts. + // Provide a complete view of the example.com zone + // including addresses of internal hosts. zone "example.com" { type master; file "example-internal.db"; @@ -2987,24 +2805,24 @@ view "internal" { view "external" { match-clients { any; }; - // Refuse recursive service to external clients. + // Refuse recursive service to external clients. recursion no; - // Provide a restricted view of the example.com zone - // containing only publicly accessible hosts. + // Provide a restricted view of the example.com zone + // containing only publicly accessible hosts. zone "example.com" { type master; file "example-external.db"; }; }; -5.2.19 zone Statement Grammar +6.2.19 zone Statement Grammar -zone zone name [class] [{ +zone zone name [class] [{ type ( master|slave|hint|stub|forward ) ; [ allow-query { address_match_list } ; ] [ allow-transfer { address_match_list } ; ] [ allow-update { address_match_list } ; ] - [ update-policy { update_policy_rule [...] } ; ] + [ update-policy { update_policy_rule[...] } ; ] [ allow-update-forwarding { address_match_list } ; ] [ also-notify { [ ip_addr ; [ip_addr ; [...]]] } ; ] [ check-names (warn|fail|ignore) ; ] @@ -3023,596 +2841,479 @@ zone zone name [class] [{ [ max-transfer-time-out number ; ] [ notify true_or_false ; ] [ pubkey number number number string ; ] - [ transfer-source (ip_addr | *) ; ] - [ sig-validity-interval number ; ] -}]; + [ transfer-source (ip4_addr | *) ; ] + [ transfer-source-v6 (ip6_addr | *) ; ] + [ sig-validity-interval number ; ]}] +; -5.2.20 zone Statement Definition and Usage +6.2.20 zone Statement Definition and Usage -5.2.20.1 Zone Types +6.2.20.1 Zone Types -master - The server has a master copy of the data for the zone and will be -able to provide authoritative answers for it. + master The server has a master copy of the data for the zone and will be + able to provide authoritative answers for it. + A slave zone is a replica of a master zone. The masters list + specifies one or more IP addresses that the slave contacts to + update its copy of the zone. If a port is specified, the slave + then checks to see if the zone is current and zone transfers will + be done to the port given. If a file is specified, then the + replica will be written to this file whenever the zone is changed, + and reloaded from this file on a server restart. Use of a file is + slave recommended, since it often speeds server start-up and eliminates + a needless waste of bandwidth. Note that for large numbers (in the + tens or hundreds of thousands) of zones per server, it is best to + use a two level naming scheme for zone file names. For example, a + slave server for the zone example.com might place the zone + contents into a file called + ex/example.com where ex/ is just the first two letters of the zone + name. (Most operating systems behave very slowly if you put 100K + files into a single directory.) + A stub zone is similar to a slave zone, except that it replicates + only the NS records of a master zone instead of the entire zone. + Stub zones are not a standard part of the DNS; they are a + peculiarity of BIND 4 and BIND 8 that relies heavily on the + particular way the zone data is structured in those servers. + BIND 9 attempts to emulate the BIND 4/8 stub zone feature for + backwards compatibility, but we do not recommend its use in new + configurations. + stub + In BIND 4/8, zone transfers of a parent zone included the NS + records from stub children of that zone. This meant that, in some + cases, users could get away with configuring child stubs only in + the master server for the parent zone. BIND 9 never mixes together + zone data from different zones in this way. Therefore, if a BIND 9 + master serving a parent zone has child stub zones configured, all + the slave servers for the parent zone also need to have the same + child stub zones configured.. + A "forward zone" is a way to configure forwarding on a per-domain + basis. A zone statement of type forward can contain a forward + and/or forwarders statement, which will apply to queries within + the domain given by the zone name. If no forwarders statement is + present or an empty list for forwarders is given, then no + forward forwarding will be done for the domain, cancelling the effects of + any forwarders in the options statement. Thus if you want to use + this type of zone to change the behavior of the global forward + option (that is, "forward first to", then "forward only", or vice + versa, but want to use the same servers as set globally) you need + to respecify the global forwarders. Domain-specific forwarding is + not yet implemented in BIND 9. + The initial set of root nameservers is specified using a "hint + zone". When the server starts up, it uses the root hints to find a + hint root nameserver and get the most recent list of root nameservers. + If no hint zone is specified for class IN, the server users a + compiled-in default set of root servers hints. Classes other than + IN have no built-in defaults hints. -slave - A slave zone is a replica of a master zone. The masters list -specifies one or more IP addresses that the slave contacts to update -its copy of the zone. If a port is specified, the slave then checks to -see if the zone is current and zone transfers will be done to the port -given. If a file is specified, then the replica will be written to this -file whenever the zone is changed, and reloaded from this file on a -server restart. Use of a file is recommended, since it often speeds -server start-up and eliminates a needless waste of bandwidth. Note -that for large numbers (in the tens or hundreds of thousands) of -zones per server, it is best to use a two level naming scheme for -zone file names. For example, a slave server for the zone -example.com might place the zone contents into a file called -ex/example.com where ex/ is just the first two letters of the zone -name. (Most operating systems behave very slowly if you put -100K files into a single directory.) +6.2.20.2 Class -stub - A stub zone is like a slave zone, except that it replicates only the -NS records of a master zone instead of the entire zone. Stub zones -are not yet implemented in BINDv9. +The zone's name may optionally be followed by a class. If a class is not +specified, class IN (for Internet ), is assumed. This is correct for the +vast majority of cases. -forward - A "forward zone" is a way to configure forwarding on a per- -domain basis. A zone statement of type forward can contain a -forward and/or forwarders statement, which will apply to queries -within the domain given by the zone name. If no forwarders -statement is present or an empty list for forwarders is given, then -no forwarding will be done for the domain, cancelling the effects -of any forwarders in the options statement. Thus if you want to -use this type of zone to change the behavior of the global forward -option (that is, "forward first to", then "forward only", or vice -versa, but want to use the same servers as set globally) you need to -respecify the global forwarders. Domain-specific forwarding is not -yet implemented in BINDv9. +The hesiod class is named for an information service from MIT's Project +Athena. It is used to share information about various systems databases, +such as users, groups, printers and so on. The keyword HS is a synonym for +hesiod. -hint - The initial set of root nameservers is specified using a "hint zone". -When the server starts up, it uses the root hints to find a root -nameserver and get the most recent list of root nameservers. If no -hint zone is specified for class IN, the server users a compiled-in -default set of root servers hints. Classes other than IN have no -built-in defaults hints. +Another MIT development is CHAOSnet, a LAN protocol created in the +mid-1970s. Zone data for it can be specified with the CHAOS class. +6.2.20.3 Zone Options -5.2.20.2 Class + allow-query See the description of allow-query under Access + Control . -The zone's name may optionally be followed by a class. If a class is not specified, -class IN (for Internet), is assumed. This is correct for the vast majority of cases. + allow-transfer See the description of allow-transfer under Access + Control . + Specifies which hosts are allowed to submit + allow-update Dynamic DNS updates for master zones. The default + is to deny updates from all hosts. -The hesiod class is named for an information service from MIT's Project Athena. -It is used to share information about various systems databases, such as users, -groups, printers and so on. The keyword HS is a synonym for hesiod. + update-policy Specifies a "Simple Secure Update" policy. See + description in Dynamic Update Policies . + Specifies which hosts are allowed to submit + Dynamic DNS updates to slave zones to be forwarded + allow-update-forwarding to the master. The default is to deny update + forwarding from all hosts. Update forwarding is + not yet implemented. + Only meaningful if notify is active for this zone. + The set of machines that will receive a DNS NOTIFY + message for this zone is made up of all the listed + also-notify nameservers (other than the primary master) for + the zone plus any IP addresses specified with + also-notify . + also-notify is not meaningful for stub zones. The + default is the empty list . -Another MIT development is CHAOSnet, a LAN protocol created in the mid-1970s. -Zone data for it can be specified with the CHAOS class. + check-names See Name Checking . + Not yet implemented in BIND 9. + See the description of dialup under Boolean + dialup Options . + Not yet implemented in BIND 9. + Only meaningful if the zone has a forwarders list. + The only value causes the lookup to fail after + forward trying the forwarders and getting no answer, while + first would allow a normal lookup to be tried. + Not yet implemented in BIND 9. + Used to override the list of global forwarders. If + it is not specified in a zone of type forward , no + forwarders forwarding is done for the zone; the global + options are not used. -5.2.20.3 Zone Options + Not yet implemented in BIND 9. + Was used in BIND 8 to specify the name of the + transaction log (journal) file for dynamic update + ixfr-base and IXFR. BIND 9 ignores the option and constructs + the name of the journal file by appending ". jnl " + to the name of the zone file. -allow-query - See the description of allow-query under -"Access Control" on page 44. + max-transfer-time-in See the description of + max-transfer-time-in under Zone Transfers . -allow-transfer - See the description of allow-transfer -under "Access Control" on page 44. + max-transfer-idle-in See the description of + max-transfer-idle-in under Zone Transfers . -allow-update - Specifies which hosts are allowed to submit -Dynamic DNS updates for master zones. -The default is to deny updates from all -hosts. + max-transfer-time-out See the description of + max-transfer-time-out under Zone Transfers . -update-policy - Specifies a "Simple Secure Update" policy. -See description in "Dynamic Update -Policies" on page 61. + max-transfer-idle-out See the description of + max-transfer-idle-out under Zone Transfers . -allow-update- -forwarding - Specifies which hosts are allowed to submit -Dynamic DNS updates to slave zones to be -forwarded to the master. The default is to -deny update forwarding from all hosts. -Update forwarding is not yet implemented. + notify See the description of notify under Boolean + Options . + In BIND 8, this option was intended for specifying + a public zone key for verification of signatures + pubkey in DNSSEC signed zones when they are loaded from + disk. BIND 9 does not verify signatures on loading + and ignores the option. -also-notify - Only meaningful if notify is active for this -zone. The set of machines that will receive a -DNS NOTIFY message for this zone is made -up of all the listed nameservers (other than -the primary master) for the zone plus any IP -addresses specified with also-notify. -also-notify is not meaningful for stub -zones. The default is the empty list. + sig-validity-interval See the description of sig-validity-interval in + Tuning . + Determines which local address will be bound to + the IPv4 TCP connection used to fetch this zone. + If not set, it defaults to a system controlled + transfer-source value which will usually be the address of the + interface "closest to" the remote end. This + address must appear in the remote end's + allow-transfer option for this zone if one is + specified. -check-names - See "Name Checking" on page 43. -Not yet implemented in BINDv9. + transfer-source-v6 Similar to transfer-source, but for zone transfers + performed using IPv6. -dialup - See the description of dialup under -"Boolean Options" on page 40. -Not yet implemented in BINDv9. +6.2.20.4 Dynamic Update Policies -forward - Only meaningful if the zone has a -forwarders list. The only value causes the -lookup to fail after trying the forwarders and -getting no answer, while first would allow -a normal lookup to be tried. -Not yet implemented in BINDv9. - -forwarders - Used to override the list of global -forwarders. If it is not specified in a zone of -type forward, no forwarding is done for the -zone; the global options are not used. - -Not yet implemented in BINDv9. - -ixfr-base - Was used in BIND 8 to specify the name of -the transaction log (journal) file for dynamic -update and IXFR. BINDv9 ignores the -option and constructs the name of the -journal file by appending ".jnl" to the name -of the zone file. - -max-transfer-time-in - See the description of -max-transfer-time-in under "Zone -Transfers" on page 46. - -max-transfer-idle-in - See the description of -max-transfer-idle-in under "Zone -Transfers" on page 46. - -max-transfer-time- -out - See the description of -max-transfer-time-out under "Zone -Transfers" on page 46. - -max-transfer-idle- -out - See the description of -max-transfer-idle-out under "Zone -Transfers" on page 46. - -notify - See the description of notify under -"Boolean Options" on page 40. - -pubkey - In BIND 8, this option was intended for -specifying a public zone key for verification -of signatures in DNSSEC signed zones -when they are loaded from disk. BINDv9 -does not verify signatures on loading and -ignores the option. - -sig-validity- -interval - See the description of sig-validity- -interval under "Tuning" on page 53. - -transfer-source - Determines which local address will be -bound to the TCP connection used to fetch -this zone. If not set, it defaults to a system -controlled value which will usually be the -address of the interface closest to the remote -end. This address must appear in the remote -end's allow-transfer option for this zone -if one is specified. - - -5.2.20.4 Dynamic Update Policies - -BINDv9 supports two alternative methods of granting clients the right to -perform dynamic updates to a zone, configured by the allow-update and +BIND 9 supports two alternative methods of granting clients the right to +perform dynamic updates to a zone, configured by the allow-update and update-policy option, respectively. -The allow-update clause works the same way as in previous versions of -BIND. It grants given clients the permission to update any record of any -name in the zone. +The allow-update clause works the same way as in previous versions of BIND. +It grants given clients the permission to update any record of any name in +the zone. -The update-policy clause is new in BINDv9 and allows more fine- -grained control over what updates are allowed. A set of rules is specified, -where each rule either grants or denies permissions for one or more names -to be updated by one or more identities. If the dynamic update request -message is signed (that is, it includes either a TSIG or SIG(0) record), the -identity of the signer can be determined. +The update-policy clause is new in BIND 9 and allows more fine-grained +control over what updates are allowed. A set of rules is specified, where +each rule either grants or denies permissions for one or more names to be +updated by one or more identities. If the dynamic update request message is +signed (that is, it includes either a TSIG or SIG(0) record), the identity +of the signer can be determined. -Rules are specified in the update-policy zone option, and are only -meaningful for master zones. When the update-policy statement is -present, it is a configuration error for the allow-update statement to be -present. The update-policy statement only examines the signer of a -message; the source address is not relevant. +Rules are specified in the update-policy zone option, and are only +meaningful for master zones. When the update-policy statement is present, it +is a configuration error for the allow-update statement to be present. The +update-policy statement only examines the signer of a message; the source +address is not relevant. -A rule definition looks like: +This is how a rule definition looks: ( grant | deny ) identity nametype name [ types ] -Each rule grants or denies privileges. Once a messages has successfully -matched a rule, the operation is immediately granted or denied and no -further rules are examined. A rule is matched when the signer matches -the identity field, the name matches the name field, and the type is -specified in the type field. +Each rule grants or denies privileges. Once a messages has successfully +matched a rule, the operation is immediately granted or denied and no +further rules are examined. A rule is matched when the signer matches the +identity field, the name matches the name field, and the type is specified +in the type field. -The identity field specifies a name or a wildcard name. The nametype -field has 4 values: name, subdomain, wildcard, and self. +The identity field specifies a name or a wildcard name. The nametype field +has 4 values: name , subdomain , wildcard , and self . -name - Matches when the updated name is the same as the name -in the name field. + name Matches when the updated name is the same as the name in the + name field. + subdomain Matches when the updated name is a subdomain of the name in the + name field. + wildcard Matches when the updated name is a valid expansion of the + wildcard name in the name field. + self Matches when the updated name is the same as the message signer. + The name field is ignored. -subdomain - Matches when the updated name is a subdomain of the -name in the name field. +If no types are specified, the rule matches all types except SIG, NS, SOA, +and NXT. Types may be specified by name, including "ANY" (ANY matches all +types except NXT, which can never be updated). -wildcard - Matches when the updated name is a valid expansion of -the wildcard name in the name field. +6.3 Zone File -self - Matches when the updated name is the same as the -message signer. The name field is ignored. +6.3.1 Types of Resource Records and When to Use Them +This section, largely borrowed from RFC 1034, describes the concept of a +Resource Record (RR) and explains when each is used. Since the publication +of RFC 1034, several new RRs have been identified and implemented in the +DNS. These are also included. -If no types are specified, the rule matches all types except SIG, NS, SOA, -and NXT. Types may be specified by name, including "ANY" (ANY -matches all types except NXT, which can never be updated). +6.3.1.1 Resource Records -5.3 Zone File - -5.3.1 Types of Resource Records and When to Use Them - -This section, largely borrowed from RFC 1034, describes the concept of a Resource -Record (RR) and explains when each is used. Since the publication of RFC 1034, -several new RRs have been identified and implemented in the DNS. These are also -included. - -5.3.1.1 Resource Records - -A domain name identifies a node. Each node has a set of resource -information, which may be empty. The set of resource information -associated with a particular name is composed of separate RRs. The -order of RRs in a set is not significant and need not be preserved by -nameservers, resolvers, or other parts of the DNS. However, sorting of -multiple RRs is permitted for optimization purposes, for example, to -specify that a particular nearby server be tried first. See "The sortlist -Statement" on page 51 and "RRset Ordering" on page 52 for details. +A domain name identifies a node. Each node has a set of resource +information, which may be empty. The set of resource information associated +with a particular name is composed of separate RRs. The order of RRs in a +set is not significant and need not be preserved by nameservers, resolvers, +or other parts of the DNS. However, sorting of multiple RRs is permitted for +optimization purposes, for example, to specify that a particular nearby +server be tried first. See The sortlist Statement and RRset Ordering for +details. The components of a Resource Record are -owner name - the domain name where the RR is found. + owner namethe domain name where the RR is found. -type - an encoded 16 bit value that specifies the type of the -resource in this resource record. Types refer to abstract -resources. + type an encoded 16 bit value that specifies the type of the resource + in this resource record. Types refer to abstract resources. + the time to live of the RR. This field is a 32 bit integer in + TTL units of seconds, and is primarily used by resolvers when they + cache RRs. The TTL describes how long a RR can be cached before + it should be discarded. -TTL - the time to live of the RR. This field is a 32 bit integer -in units of seconds, and is primarily used by resolvers -when they cache RRs. The TTL describes how long a -RR can be cached before it should be discarded. + class an encoded 16 bit value that identifies a protocol family or + instance of a protocol. -class - an encoded 16 bit value that identifies a protocol -family or instance of a protocol. + RDATA the type and sometimes class-dependent data that describes the + resource. -RDATA - the type and sometimes class-dependent data that -describes the resource. - - -The following are types of valid RRs (some of these listed, although not -obsolete, are experimental (x) or historical (h) and no longer in general +The following are types of valid RRs (some of these listed, although not +obsolete, are experimental (x) or historical (h) and no longer in general use): -A - a host address. + A a host address. + A6 an IPv6 address. + AAAA Obsolete format of IPv6 address + AFSDB(x) location of AFS database servers. Experimental. + CNAMEidentifies the canonical name of an alias. -A6 - an IPv6 address. + DNAMEfor delegation of reverse addresses. Replaces the domain name + specified with another name to be looked up. Described in RFC 2672. + HINFOidentifies the CPU and OS used by a host. + ISDN (x) representation of ISDN addresses. Experimental. + KEY stores a public key associated with a DNS name. + LOC (x) for storing GPS info. See RFC 1876. Experimental. + MX identifies a mail exchange for the domain. See RFC 974 for details. + NS the authoritative nameserver for the domain. + used in DNSSEC to securely indicate that RRs with an owner name in a + NXT certain name interval do not exist in a zone and indicate what RR + types are present for an existing name. See RFC 2535 for details. + PTR a pointer to another part of the domain name space. + RP (x) information on persons responsible for the domain. Experimental. -AAAA - Obsolete format of IPv6 address + RT (x) route-through binding for hosts that do not have their own direct + wide area network addresses. Experimental. -AFSDB - (x) location of AFS database servers. Experimental. - -CNAME - identifies the canonical name of an alias. - -DNAME - for delegation of reverse addresses. Replaces the domain -name specified with another name to be looked up. -Described in RFC 2672. - -HINFO - identifies the CPU and OS used by a host. - -ISDN - (x) representation of ISDN addresses. Experimental. - -KEY - stores a public key associated with a DNS name. - -LOC - (x) for storing GPS info. See RFC 1876. Experimental. - -MX - identifies a mail exchange for the domain. See RFC 974 -for details. - -NS - the authoritative nameserver for the domain. - -NXT - used in DNSSEC to securely indicate that RRs with an -owner name in a certain name interval do not exist in a -zone and indicate what RR types are present for an -existing name. See RFC 2535 for details. - -PTR - a pointer to another part of the domain name space. - -RP - (x) information on persons responsible for the domain. -Experimental. - -RT - (x) route-through binding for hosts that do not have their -own direct wide area network addresses. Experimental. - -SIG - ("signature") contains data authenticated in the secure -DNS. See RFC 2535 for details. - -SOA - identifies the start of a zone of authority. - -SRV - information about well known network services (replaces -WKS). - -WKS - (h) information about which well known network -services, such as SMTP, that a domain supports. -Historical, replaced by newer RR SRV. - -X25 - (x) representation of X.25 network addresses. -Experimental. + SIG ("signature") contains data authenticated in the secure DNS. See RFC + 2535 for details. + SOA identifies the start of a zone of authority. + SRV information about well known network services (replaces WKS). + WKS (h) information about which well known network services, such as + SMTP, that a domain supports. Historical, replaced by newer RR SRV. + X25 (x) representation of X.25 network addresses. Experimental. The following classes of resource records are currently valid in the DNS: -IN - the Internet system. + IN the Internet system. + For information about other, older classes of RRs, see Classes of Resource + Records in the Appendix. -For information about other, older classes of RRs, see Section B.1, -"Classes of Resource Records", on page 81 of the Appendix. - - -RDATA is the type-dependent or class-dependent data that describes the +RDATA is the type-dependent or class-dependent data that describes the resource: -A - for the IN class, a 32 bit IP address. + A for the IN class, a 32 bit IP address. -A6 - maps a domain name to an IPv6 address, with a provision -for indirection for leading "prefix" bits. + A6 maps a domain name to an IPv6 address, with a provision for + indirection for leading "prefix" bits. + CNAMEa domain name. + provides alternate naming to an entire subtree of the domain name + DNAMEspace, rather than to a single node. It causes some suffix of a + queried name to be substituted with a name from the DNAME record's + RDATA. -CNAME - a domain name. + MX a 16 bit preference value (lower is better) followed by a host name + willing to act as a mail exchange for the owner domain. + NS a fully qualified domain name. + PTR a fully qualified domain name. + SOA several fields. -DNAME - provides alternate naming to an entire subtree of the -domain name space, rather than to a single node. It -causes some suffix of a queried name to be substituted -with a name from the DNAME record's RDATA. - -MX - a 16 bit preference value (lower is better) followed by a -host name willing to act as a mail exchange for the owner -domain. - -NS - a fully qualified domain name. - -PTR - a fully qualified domain name. - -SOA - several fields. - - -The owner name is often implicit, rather than forming an integral part of -the RR. For example, many nameservers internally form tree or hash -structures for the name space, and chain RRs off nodes. The remaining -RR parts are the fixed header (type, class, TTL) which is consistent for all -RRs, and a variable part (RDATA) that fits the needs of the resource being +The owner name is often implicit, rather than forming an integral part of +the RR. For example, many nameservers internally form tree or hash +structures for the name space, and chain RRs off nodes. The remaining RR +parts are the fixed header (type, class, TTL) which is consistent for all +RRs, and a variable part (RDATA) that fits the needs of the resource being described. -The meaning of the TTL field is a time limit on how long an RR can be -kept in a cache. This limit does not apply to authoritative data in zones; it -is also timed out, but by the refreshing policies for the zone. The TTL is -assigned by the administrator for the zone where the data originates. -While short TTLs can be used to minimize caching, and a zero TTL -prohibits caching, the realities of Internet performance suggest that these -times should be on the order of days for the typical host. If a change can -be anticipated, the TTL can be reduced prior to the change to minimize -inconsistency during the change, and then increased back to its former -value following the change. +The meaning of the TTL field is a time limit on how long an RR can be kept +in a cache. This limit does not apply to authoritative data in zones; it is +also timed out, but by the refreshing policies for the zone. The TTL is +assigned by the administrator for the zone where the data originates. While +short TTLs can be used to minimize caching, and a zero TTL prohibits +caching, the realities of Internet performance suggest that these times +should be on the order of days for the typical host. If a change can be +anticipated, the TTL can be reduced prior to the change to minimize +inconsistency during the change, and then increased back to its former value +following the change. -The data in the RDATA section of RRs is carried as a combination of -binary strings and domain names. The domain names are frequently used -as "pointers" to other data in the DNS. +The data in the RDATA section of RRs is carried as a combination of binary +strings and domain names. The domain names are frequently used as "pointers" +to other data in the DNS. -5.3.1.2 Textual expression of RRs +6.3.1.2 Textual expression of RRs -RRs are represented in binary form in the packets of the DNS protocol, -and are usually represented in highly encoded form when stored in a -nameserver or resolver. In the examples provided in RFC 1034, a style -similar to that used in master files was employed in order to show the -contents of RRs. In this format, most RRs are shown on a single line, -although continuation lines are possible using parentheses. +RRs are represented in binary form in the packets of the DNS protocol, and +are usually represented in highly encoded form when stored in a nameserver +or resolver. In the examples provided in RFC 1034, a style similar to that +used in master files was employed in order to show the contents of RRs. In +this format, most RRs are shown on a single line, although continuation +lines are possible using parentheses. -The start of the line gives the owner of the RR. If a line begins with a -blank, then the owner is assumed to be the same as that of the previous -RR. Blank lines are often included for readability. +The start of the line gives the owner of the RR. If a line begins with a +blank, then the owner is assumed to be the same as that of the previous RR. +Blank lines are often included for readability. -Following the owner, we list the TTL, type, and class of the RR. Class -and type use the mnemonics defined above, and TTL is an integer before -the type field. In order to avoid ambiguity in parsing, type and class -mnemonics are disjoint, TTLs are integers, and the type mnemonic is -always last. The IN class and TTL values are often omitted from examples -in the interests of clarity. +Following the owner, we list the TTL, type, and class of the RR. Class and +type use the mnemonics defined above, and TTL is an integer before the type +field. In order to avoid ambiguity in parsing, type and class mnemonics are +disjoint, TTLs are integers, and the type mnemonic is always last. The IN +class and TTL values are often omitted from examples in the interests of +clarity. -The resource data or RDATA section of the RR are given using knowledge -of the typical representation for the data. +The resource data or RDATA section of the RR are given using knowledge of +the typical representation for the data. -For example, we might show the RRs carried in a message as: +For example, we might show the RRs carried in a message as: -ISI.EDU. MX 10 VENERA.ISI.EDU. - MX 10 VAXA.ISI.EDU -VENERA.ISI.EDU A 128.9.0.32 - A 10.1.0.52 -VAXA.ISI.EDU A 10.2.0.27 - A 128.9.0.33 + ISI.EDU. MX 10 VENERA.ISI.EDU. + MX 10 VAXA.ISI.EDU + VENERA.ISI.EDU A 128.9.0.32 + A 10.1.0.52 + VAXA.ISI.EDU A 10.2.0.27 + A 128.9.0.33 +The MX RRs have an RDATA section which consists of a 16 bit number followed +by a domain name. The address RRs use a standard IP address format to +contain a 32 bit internet address. -The MX RRs have an RDATA section which consists of a 16 bit number -followed by a domain name. The address RRs use a standard IP address -format to contain a 32 bit internet address. - -This example shows six RRs, with two RRs at each of three domain -names. +This example shows six RRs, with two RRs at each of three domain names. Similarly we might see: -XX.LCS.MIT.EDU. IN A 10.0.0.44 -CH A MIT.EDU. 2420 + XX.LCS.MIT.EDU. IN A 10.0.0.44 + CH A MIT.EDU. 2420 +This example shows two addresses for XX.LCS.MIT.EDU , each of a different +class. -This example shows two addresses for XX.LCS.MIT.EDU, each of a -different class. +6.3.2 Discussion of MX Records -5.3.2 Discussion of MX Records +As described above, domain servers store information as a series of resource +records, each of which contains a particular piece of information about a +given domain name (which is usually, but not always, a host). The simplest +way to think of a RR is as a typed pair of datum, a domain name matched with +relevant data, and stored with some additional type information to help +systems determine when the RR is relevant. -As described above, domain servers store information as a series of resource -records, each of which contains a particular piece of information about a given -domain name (which is usually, but not always, a host). The simplest way to think of -a RR is as a typed pair of datum, a domain name matched with relevant data, and -stored with some additional type information to help systems determine when the -RR is relevant. +MX records are used to control delivery of email. The data specified in the +record is a priority and a domain name. The priority controls the order in +which email delivery is attempted, with the lowest number first. If two +priorities are the same, a server is chosen randomly. If no servers at a +given priority are responding, the mail transport agent will fall back to +the next largest priority. Priority numbers do not have any absolute meaning +- they are relevant only respective to other MX records for that domain +name. The domain name given is the machine to which the mail will be +delivered. It must have an associated A record--a CNAME is not sufficient. -MX records are used to control delivery of email. The data specified in the record is -a priority and a domain name. The priority controls the order in which email -delivery is attempted, with the lowest number first. If two priorities are the same, a -server is chosen randomly. If no servers at a given priority are responding, the mail -transport agent will fall back to the next largest priority. Priority numbers do not -have any absolute meaning - they are relevant only respective to other MX records -for that domain name. The domain name given is the machine to which the mail will -be delivered. It must have an associated A record-a CNAME is not sufficient. - -For a given domain, if there is both a CNAME record and an MX record, the MX -record is in error, and will be ignored. Instead, the mail will be delivered to the -server specified in the MX record pointed to by the CNAME. +For a given domain, if there is both a CNAME record and an MX record, the MX +record is in error, and will be ignored. Instead, the mail will be delivered +to the server specified in the MX record pointed to by the CNAME. For example: -example.com. IN MX 10 mail.example.com. - IN MX 10 mail2.example.com. - IN MX 20 mail.backup.org. -mail.example.com. IN A 10.0.0.1 -mail2.example.com. IN A 10.0.0.2 - + example.com. IN MX 10 mail.example.com. + IN MX 10 mail2.example.com. + IN MX 20 mail.backup.org. + mail.example.com. IN A 10.0.0.1 + mail2.example.com. IN A 10.0.0.2 -Mail delivery will be attempted to mail.example.com and mail2.example.com (in any -order), and if neither of those succeed, delivery to mail.backup.org will be -attempted. +Mail delivery will be attempted to mail.example.com and mail2.example.com +(in any order), and if neither of those succeed, delivery to mail.backup.org +will be attempted. -5.3.3 Setting TTLs +6.3.3 Setting TTLs -The time to live of the RR field is a 32 bit integer represented in units of seconds, -and is primarily used by resolvers when they cache RRs. The TTL describes how -long a RR can be cached before it should be discarded. The following three types of -TTL are currently used in a zone file. +The time to live of the RR field is a 32 bit integer represented in units of +seconds, and is primarily used by resolvers when they cache RRs. The TTL +describes how long a RR can be cached before it should be discarded. The +following three types of TTL are currently used in a zone file. -SOA - The last field in the SOA is the negative caching TTL. This controls -how long other servers will cache no-such-domain (NXDOMAIN) -responses from you. + The last field in the SOA is the negative caching TTL. This + controls how long other servers will cache no-such-domain + SOA (NXDOMAIN) responses from you. -The maximum time for negative caching is 3 hours (3h). + The maximum time for negative caching is 3 hours (3h). -$TTL - The $TTL directive at the top of the zone file (before the SOA) gives -a default TTL for every RR without a specific TTL set. + $TTL The $TTL directive at the top of the zone file (before the SOA) + gives a default TTL for every RR without a specific TTL set. -RR TTLs - Each RR can have a TTL as the second field in the RR, which will -control how long other servers can cache the it. + RR TTLsEach RR can have a TTL as the second field in the RR, which will + control how long other servers can cache the it. +All of these TTLs default to units of seconds, though units can be +explicitly specified, for example, 1h30m . -All of these TTLs default to units of seconds, though units can be explicitly -specified, for example, 1h30m. +6.3.4 Inverse Mapping in IPv4 -5.3.4 Inverse Mapping in IPv4 - -Reverse name resolution (that is, translation from IP address to name) is achieved by -means of the in-addr.arpa domain and PTR records. Entries in the in-addr.arpa -domain are made in least-to-most significant order, read left to right. This is the -opposite order to the way IP addresses are usually written. Thus, a machine with an -IP address of 10.1.2.3 would have a corresponding in-addr.arpa name of -3.2.1.10.in-addr.arpa. This name should have a PTR resource record whose data -field is the name of the machine or, optionally, multiple PTR records if the machine -has more than one name. For example, in the example.com domain: +Reverse name resolution (that is, translation from IP address to name) is +achieved by means of the in-addr.arpa domain and PTR records. Entries in the +in-addr.arpa domain are made in least-to-most significant order, read left +to right. This is the opposite order to the way IP addresses are usually +written. Thus, a machine with an IP address of 10.1.2.3 would have a +corresponding in-addr.arpa name of +3.2.1.10.in-addr.arpa. This name should have a PTR resource record whose +data field is the name of the machine or, optionally, multiple PTR records +if the machine has more than one name. For example, in the example.com +domain: -$ORIGIN - 2.1.10.in-addr.arpa +$ORIGIN 2.1.10.in-addr.arpa +3 IN PTR foo.example.com. -3 IN PTR foo.example.com. +(Note: The $ORIGIN lines in the examples are for providing context to the +examples only--they do not necessarily appear in the actual usage. They are +only used here to indicate that the example is relative to the listed +origin.) +6.3.5 Other Zone File Directives -(Note: The $ORIGIN lines in the examples are for providing context to the examples -only-they do not necessarily appear in the actual usage. They are only used here to -indicate that the example is relative to the listed origin.) +The Master File Format was initially defined in RFC 1035 and has +subsequently been extended. While the Master File Format itself is class +independent all records in a Master File must be of the same class. -5.3.5 Other Zone File Directives +Master File Directives include $ORIGIN , $INCLUDE , and $TTL. -The Master File Format was initially defined in RFC 1035 and has subsequently -been extended. While the Master File Format itself is class independent all records -in a Master File must be of the same class. +6.3.5.1 The $ORIGIN Directive -Master File Directives include $ORIGIN, $INCLUDE, and $TTL. +Syntax: $ORIGIN < domain-name > [ < comment > ] -5.3.5.1 The $ORIGIN Directive - -Syntax: $ORIGIN [] - -$ORIGIN sets the domain name that will be appended to any unqualified records. -When a zone is first read in there is an implicit $ORIGIN . The current -$ORIGIN is appended to the domain specified in the $ORIGIN argument if it is not -absolute. +$ORIGIN sets the domain name that will be appended to any unqualified +records. When a zone is first read in there is an implicit $ORIGIN < +zone-name > . The current $ORIGIN is appended to the domain specified in the +$ORIGIN argument if it is not absolute. $ORIGIN example.com WWW CNAME MAIN-SERVER @@ -3621,37 +3322,37 @@ is equivalent to WWW.EXAMPLE.COM CNAME MAIN-SERVER.EXAMPLE.COM. -5.3.5.2 The $INCLUDE Directive +6.3.5.2 The $INCLUDE Directive -Syntax: $INCLUDE [] [] +Syntax: $INCLUDE < filename > [ < origin > ] [ < comment > ] -Read and process the file filename as if it were included into the file at this point. If -origin is specified the file is processed with $ORIGIN set to that value, otherwise -the current $ORIGIN is used. +Read and process the file filename as if it were included into the file at +this point. If origin is specified the file is processed with $ORIGIN set to +that value, otherwise the current $ORIGIN is used. -NOTE: The behavior when origin is specified differs from that described in -RFC 1035. The origin and current domain revert to the values they were prior to the -$INCLUDE once the file has been read. +NOTE: The behavior when origin is specified differs from that described in +RFC 1035. The origin and current domain revert to the values they were prior +to the $INCLUDE once the file has been read. -5.3.5.3 The $TTL Directive +6.3.5.3 The $TTL Directive -Syntax: $TTL [] +Syntax: $TTL < default-ttl > [ < comment > ] -Set the default Time To Live (TTL) for subsequent records with undefined TTLs. -Valid TTLs are of the range 0-2147483647 seconds. +Set the default Time To Live (TTL) for subsequent records with undefined +TTLs. Valid TTLs are of the range 0-2147483647 seconds. $TTL is defined in RFC 2308. -5.3.6 BIND Master File Extension: the $GENERATE Directive +6.3.6 BIND Master File Extension: the $GENERATE Directive $GENERATE -Syntax: $GENERATE [] +Syntax: $GENERATE < range > < lhs > < type > < rhs > [ < comment > ] -$GENERATE is used to create a series of resource records that only differ from each -other by an iterator. $GENERATE can be used to easily generate the sets of records -required to support sub /24 reverse delegations described in RFC 2317: Classless -IN-ADDR.ARPA delegation. +$GENERATE is used to create a series of resource records that only differ +from each other by an iterator. $GENERATE can be used to easily generate the +sets of records required to support sub /24 reverse delegations described in +RFC 2317: Classless IN-ADDR.ARPA delegation. $ORIGIN 0.0.192.IN-ADDR.ARPA. $GENERATE 1-2 0 NS SERVER$.EXAMPLE. @@ -3669,73 +3370,63 @@ is equivalent to -range - This can be one of two forms: start-stop or start-stop/step. If the -first form is used then step is set to 1. All of start, stop and step -must be positive. + This can be one of two forms: start-stop or start-stop/step. If the + range first form is used then step is set to 1. All of start, stop and + step must be positive. + lhs describes the owner name of the resource records to be created. + Any single $ symbols within the lhs side are replaced by the + lhs iterator value. To get a $ in the output use a double $ , e.g. $$ . + If the lhs is not absolute, the current $ORIGIN is appended to the + name. + type At present the only supported types are PTR, CNAME and NS. + rhs rhs is a domain name. It is processed similarly to lhs. -lhs - lhs describes the owner name of the resource records to be created. -Any single $ symbols within the lhs side are replaced by the -iterator value. To get a $ in the output use a double $, e.g. $$. If the -lhs is not absolute, the current $ORIGIN is appended to the name. +The $GENERATE directive is a BIND extension and not part of the standard +zone file format. It is not yet implemented in BIND 9. -type - At present the only supported types are PTR, CNAME and NS. +6.3.7 Signals -rhs - rhs is a domain name. It is processed similarly to lhs. - - -The $GENERATE directive is a BIND extension and not part of the standard zone file -format. It is not yet implemented in BINDv9. - -5.3.7 Signals - -Certain UNIX signals cause the name server to take specific actions, as described in -the following table. These signals can be sent using the kill command. +Certain UNIX signals cause the name server to take specific actions, as +described in the following table. These signals can be sent using the kill +command. -SIGHUP - Causes the server to read named.conf and reload the database. + SIGHUP Causes the server to read named.conf and reload the database. + SIGTERM Causes the server to clean up and exit. + SIGINT Causes the server to clean up and exit. + SIGQUIT Causes the server to clean up and exit. -SIGTERM - Causes the server to clean up and exit. + ------------------------------------------------------------------------ -SIGINT - Causes the server to clean up and exit. + Section 7. BIND 9 Security Considerations -SIGQUIT - Causes the server to clean up and exit. + 7.1 Access Control Lists +Access Control Lists (ACLs), are address match lists that you can set up and +nickname for future use in allow-query , allow-recursion , blackhole , +allow-transfer , etc. +Using ACLs allows you to have finer control over who can access your +nameserver, without cluttering up your config files with huge lists of IP +addresses. - -Section 6. Security Considerations - -6.1 Access Control Lists - -Access Control Lists (ACLs), are address match lists that you can set up and nickname for -future use in allow-query, allow-recursion, blackhole, allow-transfer, etc. - -Using ACLs allows you to have finer control over who can access your nameserver, without -cluttering up your config files with huge lists of IP addresses. - -It is a good idea to use ACLs, and to control access to your server. Limiting access to your -server by outside parties can help prevent spoofing and DoS attacks against your server. +It is a good idea to use ACLs, and to control access to your server. +Limiting access to your server by outside parties can help prevent spoofing +and DoS attacks against your server. Here is an example of how to properly apply ACLs: + // Set up an ACL named "bogusnets" that will block RFC1918 space, // which is commonly used in spoofing attacks. -acl bogusnets { 0.0.0.0/8; 1.0.0.0/8; 2.0.0.0/8; 192.0.2.0/24; -224.0.0.0/3; 10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16; }; +acl bogusnets { 0.0.0.0/8; 1.0.0.0/8; 2.0.0.0/8; 192.0.2.0/24; 224.0.0.0/3; +10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16; }; // Set up an ACL called our-nets. Replace this with the real IP numbers. -acl our-nets { x.x.x.x/24; x.x.x.x/21; }; +acl our-nets { x.x.x.x/24; x.x.x.x/21; }; options { ... @@ -3746,415 +3437,426 @@ options { blackhole { bogusnets; }; ... }; - zone "example.com" { type master; file "m/example.com"; allow-query { any; }; }; -This allows recursive queries of the server from the outside unless recursion has been -previously disabled. +This allows recursive queries of the server from the outside unless +recursion has been previously disabled. -For more information on how to use ACLs to protect your server, see the AUSCERT advisory -at +For more information on how to use ACLs to protect your server, see the +AUSCERT advisory at ftp://ftp.auscert.org.au/pub/auscert/advisory/AL-1999.004.dns_dos -6.2 chroot and setuid (for UNIX servers) + 7.2 chroot and setuid (for UNIX servers) -On UNIX servers, it is possible to run BIND in a chrooted environment (chroot()) by -specifying the `-t' option. This can help improve system security by placing BIND in a -"sandbox," which will limit the damage done if a server is compromised. +On UNIX servers, it is possible to run BIND in a chrooted environment ( +chroot() ) by specifying the " -t " option. This can help improve system +security by placing BIND in a "sandbox," which will limit the damage done if +a server is compromised. -Another useful feature in the UNIX version of BIND is the ability to run the daemon as a -nonprivileged user ( -u ). We suggest running as a nonprivileged user when using the -chroot feature. +Another useful feature in the UNIX version of BIND is the ability to run the +daemon as a nonprivileged user ( -u user ). We suggest running as a +nonprivileged user when using the chroot feature. -Here is an example command line to load BIND in a chroot() sandbox, -/var/named, and to run named setuid to user 202: +Here is an example command line to load BIND in a chroot() sandbox, +/var/named , and to run named setuid to user 202: /usr/local/bin/named -u 202 -t /var/named -6.2.1 The chroot Environment + 7.2.1 The chroot Environment -In order for a chroot() environment to work properly in a particular directory (for -example, /var/named), you will need to set up an environment that includes -everything BIND needs to run. From BIND's point of view, /var/named is the root of -the filesystem. You will need /dev/null, and any library directories and files that -BIND needs to run on your system. Please consult your operating system's -instructions if you need help figuring out which library files you need to copy over -to the chroot() sandbox. +In order for a chroot() environment to work properly in a particular +directory (for example, /var/named ), you will need to set up an environment +that includes everything BIND needs to run. From BIND's point of view, +/var/named is the root of the filesystem. You will need /dev/null , and any +library directories and files that BIND needs to run on your system. Please +consult your operating system's instructions if you need help figuring out +which library files you need to copy over to the chroot() sandbox. -If you are running an operating system that supports static binaries, you can also -compile BIND statically and avoid the need to copy system libraries over to your -chroot() sandbox. +If you are running an operating system that supports static binaries, you +can also compile BIND statically and avoid the need to copy system libraries +over to your chroot() sandbox. -6.2.2 Using the setuid Function + 7.2.2 Using the setuid Function -Prior to running the named daemon, use the touch utility (to change file access and -modification times) or the chown utility (to set the user id and/or group id) on files to -which you want BIND to write. +Prior to running the named daemon, use the touch utility (to change file +access and modification times) or the chown utility (to set the user id +and/or group id) on files to which you want BIND to write. -6.3 Dynamic Updates + 7.3 Dynamic Updates -Access to the dynamic update facility should be strictly limited. In earlier versions of BIND -the only way to do this was based on the IP address of the host requesting the update. -BINDv9 also supports authenticating updates cryptographically by means of transaction -signatures (TSIG). The use of TSIG is strongly recommended. +Access to the dynamic update facility should be strictly limited. In earlier +versions of BIND the only way to do this was based on the IP address of the +host requesting the update. BIND 9BIND 9 also supports authenticating +updates cryptographically by means of transaction signatures (TSIG). The use +of TSIG is strongly recommended. -Some sites choose to keep all dynamically updated DNS data in a subdomain and delegate -that subdomain to a separate zone. This way, the top-level zone containing critical data such -as the IP addresses of public web and mail servers need not allow dynamic update at all. +Some sites choose to keep all dynamically updated DNS data in a subdomain +and delegate that subdomain to a separate zone. This way, the top-level zone +containing critical data such as the IP addresses of public web and mail +servers need not allow dynamic update at all. + ------------------------------------------------------------------------ + + Section 8. Troubleshooting + 8.1 Common Problems -Section 7. Troubleshooting + 8.1.1 It's not working; how can I figure out what's wrong? -7.1 Common Log Messages and What They Mean +The best solution to solving installation and configuration issues is to +take preventative measures by setting up logging files beforehand. (See the +sample configurations) in Section 3. The log files provide a source of hints +and information that can be used to figure out what went wrong and how to +fix the problem. -o lame server + 8.2 Incrementing and Changing the Serial Number -ns named[111]: Lame server on 'www.example.com' (in 'example.com'?): -[192.168.0.2].53 'ns2.example.com' +Zone serial numbers are just numbers--they aren't date related. A lot of +people set them to a number that represents a date, usually of the form +YYYYMMDDRR. A number of people have been testing these numbers for Y2K +compliance and have set the number to the year 2000 to see if it will work. +They then try to restore the old serial number. This will cause problems +because serial numbers are used to indicate that a zone has been updated. If +the serial number on the slave server is lower than the serial number on the +master, the slave server will attempt to update its copy of the zone. -This is a harmless error message. It means that the server at 192.168.0.2 (ns2.example.com) is -listed as a nameserver for "example.com", but it doesn't really know anything about -example.com. +Setting the serial number to a lower number on the master server than the +slave server means that the slave will not perform updates to its copy of +the zone. -If this is a zone under your control, check each of the nameservers to ensure that they are -configured to answer questions properly. +The solution to this is to add 2147483647 (2^31-1) to the number, reload the +zone and make sure all slaves have updated to the new zone serial number, +then reset the number to what you want it to be, and reload the zone again. -If it's a zone out on the Internet, it would be nice to notify the owners of the domain in -question so that they can take a look at it. In practice, though, not many people have time to -do this. + 8.3 Where Can I Get Help? -o bad referral +The Internet Software Consortium (ISC) offers a wide range of support and +service agreements for BIND and DHCP servers. Four levels of premium support +are available and each level includes support for all ISC programs, +significant discounts on products and training, and a recognized priority on +bug fixes and non-funded feature requests. In addition, ISC offers a +standard support agreement package which includes services ranging from bug +fix announcements to remote support. It also includes training in BIND and +DHCP. -ns named[111]: bad referral (other.com !< subdomain.other.com) - -This indicates that your nameserver (ns.example.com) queried the nameserver for -example2.com to find out how to get to subdomain.example2.com. The name server -example2.com told your nameserver that subdomain.example2.com was delegated to some -other.example2.com, so your nameserver queried that. - -someother.example2.com didn't think that subdomain.example2.com had been delegated to it, so -it referred your server (ns.example.com) back to the example2.com nameserver. - -o not authoritative for - -ns named-xfer[111]: [192.168.0.1] not authoritative for example.com, SOA -query got rcode 0, aa 0, ancount 1, aucount 0 - -This error usually shows up on a slave server. It indicates that the master server is not -answering authoritatively for the zone. This usually happens when the zone is rejected -(while named is loading) on the master server. Check the logs on the master server. If -ancount -- 0, you may be pointing at the wrong master server for the zone. - -o rejected zone - -ns named[111]: master zone "example.com" (IN) rejected due to errors -(serial111) - -This indicates that the example.com zone was rejected because of an error in the zone file. -Check the lines above this error. named will usually tell you what it didn't like and where to -find it in the zone file. - -o no NS RRs found - -ns named[111]: Zone "example.com" (file example.com.db): no NS RRs found at -zonetop - -The example.com.db file is missing NS records at the top of the zone (in the SOA section). -Check to make sure they exist and that there is white space (spaces or tabs) in front of them. -White spaces matter here. - -o no default TTL set - -ns named[111]: Zone "example.com" (file example.com.db): No default TTL set -using SOA minimum instead - -You will need to add a $TTL to the top of the example.com.db zone file. See RFC 2308, or -"Setting TTLs" on page 67 for information on how to use $TTL. - -o no root nameserver for class - -findns: No root nameservers for class IN? - -Your nameserver is having problems finding the root nameservers. Check your root hints file -to make sure it is not corrupted. Also, make sure that your nameserver can reach the Internet. - -If you are running an internal root nameserver, make sure it is configured properly and is -answering queries. - -o address already in use - -ctl_server: bind: Address already in use - -This usually indicates that another copy of BIND is already running. Verify that you have -killed old copies of the daemon. - -This can also pop up if you originally ran named as "root" and now run it as a regular user. -named may have left behind an ndc control socket that is owned by root if it crashed, or was -not killed gracefully. - -This means that the regular user wouldn't be able to delete it, so it would think named is still -running. The solution is to remove any ndc sockets in /usr/local/etc, or /var/run, etc. - -7.2 Common Problems - -7.2.1 It's not working; how can I figure out what's wrong? - -The best solution to solving installation and configuration issues is to take -preventative measures by setting up logging files beforehand (see the sample -configurations in Section 3.1 "Sample Configuration and Logging", page 9). The -log files provide a source of hints and information that can be used to figure out -what went wrong and how to fix the problem. - -7.3 Incrementing and Changing the Serial Number - -Zone serial numbers are just numbers-they aren't date related. A lot of people set them to a -number that represents a date, usually of the form YYYYMMDDRR. A number of people -have been testing these numbers for Y2K compliance and have set the number to the year -2000 to see if it will work. They then try to restore the old serial number. This will cause -problems, because serial numbers are used to indicate that a zone has been updated. If the -serial number on the secondary server is lower than the serial number on the primary, the -secondary server will attempt to update its copy of the zone. - -Setting the serial number to a lower number on the primary server than the secondary server -means that the secondary will not perform updates to its copy of the zone. - -The solution to this is to add 2147483647 (2^31-1) to the number, reload the zone and make -sure all secondaries have updated to the new zone serial number, then reset the number to -what you want it to be, and reload the zone again. - -7.4 Where Can I Get Help? - -The Internet Software Consortium (ISC) offers a wide range of support and service -agreements for BIND and DHCP servers. Four levels of premium support are available and -each level includes support for all ISC programs, significant discounts on products and -training, and a recognized priority on bug fixes and non-funded feature requests. In addition, -ISC offers a standard support agreement package which includes services ranging from bug -fix announcements to remote support. It also includes training in BIND and DHCP. - -To discuss arrangements for support, contact info@isc.org or visit the ISC web page at +To discuss arrangements for support, contact info@isc.org or visit the ISC +web page at http://www.isc.org/services/support/ to read more. + ------------------------------------------------------------------------ +APPENDICES - Appendices +Acknowledgements -Appendix A. Acknowledgements +A Brief History of the DNS and BIND -A.1 A Brief History of the DNS and BIND - -Although the "official" beginning of the Domain Name System occurred in 1984 with the -publication of RFC 920, the core of the new system was described in 1983 in RFCs 882 and -883. From 1984 to 1987, the ARPAnet (the precursor to today's Internet) became a testbed -of experimentation for developing the new naming/addressing scheme in an rapidly -expanding, operational network environment. New RFCs were written and published in -1987 that modified the original documents to incorporate improvements based on the -working model. RFC 1034, "Domain Names - Concepts and Facilities," and RFC 1035, -"Domain Names - Implementation and Specification" were published and became the +Although the "official" beginning of the Domain Name System occurred in 1984 +with the publication of RFC 920, the core of the new system was described in +1983 in RFCs 882 and 883. From 1984 to 1987, the ARPAnet (the precursor to +today's Internet) became a testbed of experimentation for developing the new +naming/addressing scheme in an rapidly expanding, operational network +environment. New RFCs were written and published in 1987 that modified the +original documents to incorporate improvements based on the working model. +RFC 1034, "Domain Names-Concepts and Facilities," and RFC 1035, "Domain +Names-Implementation and Specification" were published and became the standards upon which all DNS implementations are built. -The first working domain name server, called "Jeeves," was written in 1983-84 by Paul -Mockapetris for operation on DEC Tops-20 machines located at the University of Southern -California's Information Sciences Institute (USC-ISI) and SRI International's Network -Information Center (SRI-NIC). A DNS server for Unix machines, the Berkeley Internet -Name Domain (BIND) package, was written soon after by a group of graduate students at -the University of California at Berkeley under a grant from the US Defense Advanced -Research Projects Administration (DARPA). Versions of BIND through 4.8.3 were -maintained by the Computer Systems Research Group (CSRG) at UC Berkeley. Douglas -Terry, Mark Painter, David Riggle and Songnian Zhou made up the initial BIND project -team. After that, additional work on the software package was done by Ralph Campbell. -Kevin Dunlap, a Digital Equipment Corporation employee on loan to the CSRG, worked on -BIND for 2 years, from 1985 to 1987. Many other people also contributed to BIND -development during that time: Doug Kingston, Craig Partridge, Smoot Carl-Mitchell, Mike -Muuss, Jim Bloom and Mike Schwartz. BIND maintenance was subsequently handled by -Mike Karels and O. Kure. +The first working domain name server, called "Jeeves," was written in +1983-84 by Paul Mockapetris for operation on DEC Tops-20 machines located at +the University of Southern California's Information Sciences Institute +(USC-ISI) and SRI International's Network Information Center (SRI-NIC). A +DNS server for Unix machines, the Berkeley Internet Name Domain (BIND) +package, was written soon after by a group of graduate students at the +University of California at Berkeley under a grant from the US Defense +Advanced Research Projects Administration (DARPA). Versions of BIND through +4.8.3 were maintained by the Computer Systems Research Group (CSRG) at UC +Berkeley. Douglas Terry, Mark Painter, David Riggle and Songnian Zhou made +up the initial BIND project team. After that, additional work on the +software package was done by Ralph Campbell. Kevin Dunlap, a Digital +Equipment Corporation employee on loan to the CSRG, worked on BIND for 2 +years, from 1985 to 1987. Many other people also contributed to BIND +development during that time: Doug Kingston, Craig Partridge, Smoot +Carl-Mitchell, Mike Muuss, Jim Bloom and Mike Schwartz. BIND maintenance was +subsequently handled by Mike Karels and O. Kure. -BIND versions 4.9 and 4.9.1 were released by Digital Equipment Corporation (now Compaq -Computer Corporation). Paul Vixie, then a DEC employee, became BIND's primary -caretaker. Paul was assisted by Phil Almquist, Robert Elz, Alan Barrett, Paul Albitz, Bryan -Beecher, Andrew Partan, Andy Cherenson, Tom Limoncelli, Berthold Paffrath, Fuat Baran, -Anant Kumar, Art Harkin, Win Treese, Don Lewis, Christophe Wolfhugel, and others. +BIND versions 4.9 and 4.9.1 were released by Digital Equipment Corporation +(now Compaq Computer Corporation). Paul Vixie, then a DEC employee, became +BIND's primary caretaker. Paul was assisted by Phil Almquist, Robert Elz, +Alan Barrett, Paul Albitz, Bryan Beecher, Andrew Partan, Andy Cherenson, Tom +Limoncelli, Berthold Paffrath, Fuat Baran, Anant Kumar, Art Harkin, Win +Treese, Don Lewis, Christophe Wolfhugel, and others. -BIND Version 4.9.2 was sponsored by Vixie Enterprises. Paul Vixie became BIND's -principal architect/programmer. +BIND Version 4.9.2 was sponsored by Vixie Enterprises. Paul Vixie became +BIND's principal architect/programmer. -BIND versions from 4.9.3 onward have been developed and maintained by the Internet -Software Consortium with support being provided by ISC's sponsors. As co-architects/ -programmers, Bob Halley and Paul Vixie released the first production-ready version of -BIND version 8 in May 1997. +BIND versions from 4.9.3 onward have been developed and maintained by the +Internet Software Consortium with support being provided by ISC's sponsors. +As co-architects/programmers, Bob Halley and Paul Vixie released the first +production-ready version of BIND version 8 in May 1997. -BIND development work is made possible today by the sponsorship of several corporations, -and by the tireless work efforts of numerous individuals. +BIND development work is made possible today by the sponsorship of several +corporations, and by the tireless work efforts of numerous individuals. -Appendix B. Historical DNS Information +Historical DNS Information -B.1 Classes of Resource Records +Classes of Resource Records -B.1.1 HS = hesiod +HS = hesiod -The hesiod class is an information service developed by MIT's Project Athena. It is -used to share information about various systems databases, such as users, groups, -printers and so on. The keyword hs is a synonym for hesiod. +The hesiod class is an information service developed by MIT's Project +Athena. It is used to share information about various systems databases, +such as users, groups, printers and so on. The keyword hs is a synonym for +hesiod. -B.1.2 CH = chaos +CH = chaos -The chaos class is used to specify zone data for the MIT-developed CHAOSnet, a -LAN protocol created in the mid-1970s. +The chaos class is used to specify zone data for the MIT-developed CHAOSnet, +a LAN protocol created in the mid-1970s. -Appendix C. Bibliography (and Suggested Reading) +General DNS Reference Information -C.1 Request for Comments (RFCs) +IPv6 addresses (A6) -Specification documents for the Internet protocol suite, including the DNS, are published as -part of the Request for Comments (RFCs) series of technical notes. The standards -themselves are defined by the Internet Engineering Task Force (IETF) and the Internet -Engineering Steering Group (IESG). RFCs can be obtained online via FTP at -ftp://www.isi.edu/in-notes/RFCxxx.txt (where xxx is the number of the RFC). RFCs are also -available via the Web at http://www.ietf.org/rfc/. +IPv6 addresses are 128-bit identifiers for interfaces and sets of interfaces +which were introduced in the DNS to facilitate scalable Internet routing. +There are three types of addresses: Unicast , an identifier for a single +interface; Anycast , an identifier for a set of interfaces; and Multicast , +an identifier for a set of interfaces. Here we describe the global Unicast +address scheme. For more information, see RFC 2374. -C.1.1 Standards +The aggregatable global Unicast address format is as follows: -RFC974. Partridge, C. Mail Routing and the Domain System. January 1986. -RFC1034. Mockapetris, P.V. Domain Names - Concepts and Facilities. P.V. November -1987. -RFC1035. Mockapetris, P. V. Domain Names - Implementation and Specification. + 3 13 8 24 16 64 bits + FP TLA ID RES NLA ID SLA ID Interface ID + <------ Public Topology + ------> + <-Site Topology-> + + <------ Interface Identifier + ------> + +Where + + FP = Format Prefix (001) + TLA ID = Top-Level Aggregation Identifier + RES = Reserved for future use + NLA ID = Next-Level Aggregation Identifier + SLA ID = Site-Level Aggregation Identifier + INTERFACE ID= Interface Identifier + +The Public Topology is provided by the upstream provider or ISP, and +(roughly) corresponds to the IPv4 network section of the address range. The +Site Topology is where you can subnet this space, much the same as +subnetting an IPv4 class A or B network into class Cs. The Interface +Identifier is the address of an individual interface on a given network. +(With IPv6, addresses belong to interfaces rather than machines.) + +The subnetting capability of IPv6 is much more flexible than that of IPv4: +subnetting can now be carried out on bit boundaries, in much the same way as +Classless InterDomain Routing (CIDR). + +The internal structure of the Public Topology for an A6 global unicast +address consists of: + + + + 3 13 8 24 + FPTLA ID RES NLA ID + +A 3 bit FP (Format Prefix) of 001 indicates this is a global Unicast +address. FP lengths for other types of addresses may vary. + +13 TLA (Top Level Aggregator) bits give the prefix of your top-level IP +backbone carrier. + +8 Reserved bits + +24 bits for Next Level Aggregators. This allows organizations with a TLA to +hand out portions of their IP space to client organizations, so that the +client can then split up the network further by filling in more NLA bits, +and hand out IPv6 prefixes to their clients, and so forth. + +There is no particular structure for the Site topology section. +Organizations can allocate these bits in any way they desire, in the same +way as they would subnet an IPv4 class A (8-bit prefix) network. + +The Interface Identifier must be unique on that network. On ethernet +networks, one way to ensure this is to set the address to the first three +bytes of the hardware address, "FFFE", then the last three bytes of the +hardware address. The lowest significant bit of the first byte should then +be complemented. Addresses are written as 32-bit blocks separated with a +colon, and leading zeros of a block may be omitted, for example: + +3ffe:8050:201:9:a00:20ff:fe81:2b32 + +IPv6 address specifications are likely to contain long strings of zeros, so +the architects have included a shorthand for specifying them. The double +colon (`::') indicates the longest possible string of zeros that can fit, +and can be used only once in an address. + +Bibliography (and Suggested Reading) + +Request for Comments (RFCs) + +Specification documents for the Internet protocol suite, including the DNS, +are published as part of the Request for Comments (RFCs) series of technical +notes. The standards themselves are defined by the Internet Engineering Task +Force (IETF) and the Internet Engineering Steering Group (IESG). RFCs can be +obtained online via FTP at +ftp://www.isi.edu/in-notes/RFCxxx.txt (where xxx is the number of the RFC). +RFCs are also available via the Web at http://www.ietf.org/rfc/ . + +Standards + +RFC974. Partridge, C. Mail Routing and the Domain System . January 1986. + +RFC1034. Mockapetris, P.V. Domain Names - Concepts and Facilities . P.V. November 1987. -C.1.2 Proposed Standards +RFC1035. Mockapetris, P. V. Domain Names - Implementation and Specification +. November 1987. -RFC2181. Elz, R., R. Bush. Clarifications to the DNS Specification. July 1997. +Proposed Standards -RFC2308. Andrews, M. Negative Caching of DNS Queries. March 1998. +RFC2181. Elz, R., R. Bush. Clarifications to the DNS Specification . July +1997. -RFC1995. Ohta, M. Incremental Zone Transfer in DNS. August 1996. +RFC2308. Andrews, M. Negative Caching of DNS Queries . March 1998. -RFC1996. Vixie, P. A Mechanism for Prompt Notification of Zone Changes. August 1996. +RFC1995. Ohta, M. Incremental Zone Transfer in DNS . August 1996. -RFC2136. Vixie, P., S. Thomson, Y. Rekhter, J. Bound. Dynamic Updates in the Domain -Name System. April 1997. +RFC1996. Vixie, P. A Mechanism for Prompt Notification of Zone Changes . +August 1996. -RFC2845. Vixie, P., O. Gudmundsson, D. Eastlake 3rd, B. Wellington. Secret Key -Transaction Authentication for DNS (TSIG). May 2000. +RFC2136. Vixie, P., S. Thomson, Y. Rekhter, J. Bound. Dynamic Updates in the +Domain Name System . April 1997. -C.1.3 Proposed Standards Still Under Development +RFC2845. Vixie, P., O. Gudmundsson, D. Eastlake 3rd, B. Wellington. Secret +Key Transaction Authentication for DNS (TSIG) . May 2000. + +Proposed Standards Still Under Development Note: the following list of RFCs are undergoing major revision by the IETF. -RFC1886. Thomson, S., C. Huitema. DNS Extensions to support IP version 6. S. December -1995. +RFC1886. Thomson, S., C. Huitema. DNS Extensions to support IP version 6 . +S. December 1995. -RFC2065. Eastlake, 3rd, D., C. Kaufman. Domain Name System Security Extensions. -January 1997. +RFC2065. Eastlake, 3rd, D., C. Kaufman. Domain Name System Security +Extensions . January 1997. -RFC2137. Eastlake, 3rd, D. Secure Domain Name System Dynamic Update. April 1997. - -C.1.4 Other Important RFCs About DNS Implementation - -RFC1535. Gavron, E. A Security Problem and Proposed Correction With Widely Deployed -DNS Software. October 1993. - -RFC1536. Kumar, A., J. Postel, C. Neuman, P. Danzig, S. Miller. Common DNS -Implementation Errors and Suggested Fixes. October 1993. - -RFC1982. Elz, R., R. Bush. Serial Number Arithmetic. August 1996. - -C.1.5 Resource Record Types - -RFC1183. Everhart, C.F., L. A. Mamakos, R. Ullmann, P. Mockapetris. New DNS RR -Definitions. October 1990. - -RFC1706. Manning, B., R. Colella. DNS NSAP Resource Records. October 1994. - -RFC2168. Daniel, R., M. Mealling. Resolution of Uniform Resource Identifiers using the -Domain Name System. June 1997. - -RFC1876. Davis, C., P. Vixie, T. Goodwin, I. Dickinson. A Means for Expressing Location -Information in the Domain Name System. January 1996. - -RFC2052. Gulbrandsen, A., P. Vixie. A DNS RR for Specifying the Location of Services. -October 1996. - -RFC2163. Allocchio, A. Using the Internet DNS to Distribute MIXER Conformant Global -Address Mapping. January 1998. - -RFC2230. Atkinson, R. Key Exchange Delegation Record for the DNS. October 1997. - -C.1.6 DNS and the Internet - -RFC1101. Mockapetris, P. V. DNS Encoding of Network Names and Other Types. April -1989. - -RFC1123. Braden, R. Requirements for Internet Hosts - Application and Support. October -1989. - -RFC1591. Postel, J. Domain Name System Structure and Delegation. March 1994. - -RFC2317. Eidnes, H., G. de Groot, P. Vixie. Classless IN-ADDR.ARPA Delegation. March -1998. - -C.1.7 DNS Operations - -RFC1537. Beertema, P. Common DNS Data File Configuration Errors. October 1993. - -RFC1912. Barr, D. Common DNS Operational and Configuration Errors. February 1996. - -RFC2182. Elz, R. R. Bush, S. Bradner, M. Patton. Selection and Operation of Secondary -DNS Servers. July 1997. - -RFC2219. Hamilton, M., R. Wright. Use of DNS Aliases for Network Services. October +RFC2137. Eastlake, 3rd, D. Secure Domain Name System Dynamic Update . April 1997. -C.1.8 Other DNS-related RFCs +Other Important RFCs About DNS Implementation -Note: the following list of RFCs, although DNS-related, are not concerned with -implementing software. +RFC1535. Gavron, E. A Security Problem and Proposed Correction With Widely +Deployed DNS Software. October 1993. -RFC1464. Rosenbaum, R. Using the Domain Name System To Store Arbitrary String -Attributes. May 1993. +RFC1536. Kumar, A., J. Postel, C. Neuman, P. Danzig, S. Miller. Common DNS +Implementation Errors and Suggested Fixes . October 1993. -RFC1713. Romao, A. Tools for DNS Debugging. November 1994. +RFC1982. Elz, R., R. Bush. Serial Number Arithmetic . August 1996. -RFC1794. Brisco, T. DNS Support for Load Balancing. April 1995. +Resource Record Types -RFC2240. Vaughan, O. A Legal Basis for Domain Name Allocation. November1997. +RFC1183. Everhart, C.F., L. A. Mamakos, R. Ullmann, P. Mockapetris. New DNS +RR Definitions . October 1990. -RFC2345. Klensin, J., T. Wolf, G. Oglesby. Domain Names and Company Name Retrieval. +RFC1706. Manning, B., R. Colella. DNS NSAP Resource Records . October 1994. + +RFC2168. Daniel, R., M. Mealling. Resolution of Uniform Resource Identifiers +using the Domain Name System. June 1997. + +RFC1876. Davis, C., P. Vixie, T. Goodwin, I. Dickinson. A Means for +Expressing Location Information in the Domain Name System . January 1996. + +RFC2052. Gulbrandsen, A., P. Vixie. A DNS RR for Specifying the Location of +Services. October 1996. + +RFC2163. Allocchio, A. U sing the Internet DNS to Distribute MIXER +Conformant Global Address Mapping . January 1998. + +RFC2230. Atkinson, R. Key Exchange Delegation Record for the DNS . October +1997. + +DNS and the Internet + +RFC1101. Mockapetris, P. V. DNS Encoding of Network Names and Other Types . +April 1989. + +RFC1123. Braden, R. Requirements for Internet Hosts - Application and +Support . October 1989. + +RFC1591. Postel, J. D omain Name System Structure and Delegation . March +1994. + +RFC2317. Eidnes, H., G. de Groot, P. Vixie. Classless IN-ADDR.ARPA +Delegation . March 1998. + +DNS Operations + +RFC1537. Beertema, P. Common DNS Data File Configuration Errors . October +1993. + +RFC1912. Barr, D. Common DNS Operational and Configuration Errors . February +1996. + +RFC1912. Barr, D. Common DNS Operational and Configuration Errors . February +1996. + +RFC2010. Manning, B., P. Vixie. Operational Criteria for Root Name Servers. +October 1996. + +RFC2219. Hamilton, M., R. Wright. Use of DNS Aliases for Network Services. +October 1997. + +Other DNS-related RFCs + +Note: the following list of RFCs, although DNS-related, are not concerned +with implementing software. + +RFC1464. Rosenbaum, R. Using the Domain Name System To Store Arbitrary +String Attributes . May 1993. + +RFC1713. Romao, A. Tools for DNS Debugging . November 1994. + +RFC1794. Brisco, T. DNS Support for Load Balancing . April 1995. + +RFC2240. Vaughan, O. A Legal Basis for Domain Name Allocation . +November1997. + +RFC2345. Klensin, J., T. Wolf, G. Oglesby. Domain Names and Company Name +Retrieval . May 1998. + +RFC2352. Vaughan, O. A Convention For Using Legal Names as Domain Names . May 1998. -RFC2352. Vaughan, O. A Convention For Using Legal Names as Domain Names. May 1998. +Obsolete and Unimplemented Experimental RRs -C.1.9 Obsolete and Unimplemented Experimental RRs +RFC1712. Farrell, C., M. Schulze, S. Pleitner, D. Baldoni. DNS Encoding of +Geographical Location . November 1994. -RFC1712. Farrell, C., M. Schulze, S. Pleitner, D. Baldoni. DNS Encoding of Geographical -Location. November 1994. +Internet Drafts -C.2 Internet Drafts - -Internet Drafts (IDs) are rough-draft working documents of the Internet Engineering Task -Force. They are, in essence, RFCs in the preliminary stages of development. Implementors -are cautioned not to regard IDs as archival, and they should not be quoted or cited in any -formal documents unless accompanied by the disclaimer that they are "works in progress." -IDs have a lifespan of six months after which they are deleted unless updated by their +Internet Drafts (IDs) are rough-draft working documents of the Internet +Engineering Task Force. They are, in essence, RFCs in the preliminary stages +of development. Implementors are cautioned not to regard IDs as archival, +and they should not be quoted or cited in any formal documents unless +accompanied by the disclaimer that they are "works in progress." IDs have a +lifespan of six months after which they are deleted unless updated by their authors. -C.3 Electronic Mail Communication - -Wellington, Brian (bwellington@tislabs.com). DNSSEC usage document. E-mail to David Conrad -(David_Conrad@isc.org). 15 March 1999. - -Wellington, Brian (bwellington@tislabs.com). TSIG guide for BIND 8.2+. E-mail to private -mailing list (private communication). 22 April 1999. - -C.4 Other BIND Documents - -Albitz, Paul and Cricket Liu. 1998. DNS and BIND. Sebastopol, CA: O'Reilly and Associates. - +Other BIND Documents +Albitz, Paul and Cricket Liu. 1998. DNS and BIND . Sebastopol, CA: O'Reilly +and Associates. + ------------------------------------------------------------------------