diff --git a/doc/draft/draft-ietf-dnsext-ipv6-addresses-01.txt b/doc/draft/draft-ietf-dnsext-ipv6-addresses-01.txt new file mode 100644 index 0000000000..cff95c3950 --- /dev/null +++ b/doc/draft/draft-ietf-dnsext-ipv6-addresses-01.txt @@ -0,0 +1,335 @@ + + +DNSEXT Working Group Randy Bush (ed.) + Alain Durand (ed.) + Bob Fink (ed.) + Olafur Gudmundsson (ed.) + Tony Hain (ed.) +INTERNET-DRAFT March 2002 + + + +Updates: RFC 1886, RFC 2673, RFC 2874 + + + + Representing IPv6 addresses in DNS. + + +Status of this Memo + + This document is an Internet-Draft and is in full conformance with + all provisions of Section 10 of RFC 2026. + + Internet-Drafts are working documents of the Internet Engineering + Task Force (IETF), its areas, and its working groups. Note that + other groups may also distribute working documents as Internet- + Drafts. + + Internet-Drafts are draft documents valid for a maximum of six months + and may be updated, replaced, or obsoleted by other documents at any + time. It is inappropriate to use Internet-Drafts as reference + material or to cite them other than as ``work in progress.'' + + The list of current Internet-Drafts can be accessed at + http://www.ietf.org/ietf/1id-abstracts.txt + + The list of Internet-Draft Shadow Directories can be accessed at + http://www.ietf.org/shadow.html + + Comments should be sent to the authors or the DNSEXT WG mailing list + namedroppers@ops.ietf.org + + This draft expires on September 1, 2002. + + Copyright Notice + + Copyright (C) The Internet Society (2002). All rights reserved. + + + + + + +Expires 1/September/2002 DNSEXT [Page 1] + +INTERNET-DRAFT Representation of IPv6 addresses in DNS. March 2002 + + +Abstract + + This document clarifies and updates the standards status of RFCs that + define direct and reverse map of IPv6 addresses in DNS. This document + moves the A6 and Bit label specifications to experimental status. + + + + +1 - Introduction + + The IETF had begun the process of standardizing two different address + formats for IPv6 addresses AAAA[RFC1886] and A6[RFC2874] and both are + at proposed standard. This had led to confusion and conflicts on + which one to deploy. It is important for deployment that any + confusion in this area be cleared up, as there is a feeling in the + community that having more than one choice will lead to delays in the + deployment of IPv6. The goal of this document is to clarify the + situation. + + This document is based on extensive technical discussion on various + relevant working groups mailing lists and a joint DNSEXT and NGTRANS + meeting at the 51st IETF in August 2001. This document attempts to + capture the sense of the discussions and reflect them in this + document to represent the consensus of the community. + + The main arguments and the issues are covered in a separate + document[Tradeoff] that reflects the current understanding of the + issues. This document summarizes the outcome of these discussions. + + The issue of the root of reverse IPv6 address map is outside the + scope of this document and is covered in a different + document[RFC3152]. + +1.1 Standards action taken + + This document changes the status of RFCs 2673 and 2874 from Proposed + Standard to Experimental. + + + + + + + + + + + + + +Expires 1/September/2002 DNSEXT [Page 2] + +INTERNET-DRAFT Representation of IPv6 addresses in DNS. March 2002 + + +2 - IPv6 addresses: AAAA RR vs A6 RR + + Working group consensus as perceived by the chairs of the DNSEXT and + NGTRANS working groups is that: + + a) AAAA records are preferable at the moment for production + deployment of IPv6, and + + b) that A6 records have interesting properties that need to be + better understood before deployment. + + c) It is not known if the benefits of A6 outweigh the costs and + risks. + + +2.1 Rationale + + There are several potential issues with A6 RRs that stem directly + from the feature that makes them different from AAAA RRs: the ability + to build up addresses via chaining. + + Resolving a chain of A6 RRs involves resolving a series of what are + nearly-independent queries. Each of these sub-queries takes some + non-zero amount of time, unless the answer happens to be in the + resolver's local cache already. Other things being equal, we expect + that the time it takes to resolve an N-link chain of A6 RRs will be + roughly proportional to N. What data we have suggests that users are + already impatient with the length of time it takes to resolve A RRs + in the IPv4 Internet, which suggests that users are not likely to be + patient with significantly longer delays in the IPv6 Internet, but + terminating queries prematurely is both a waste of resources and + another source of user frustration. Thus, we are forced to conclude + that indiscriminate use of long A6 chains is likely to lead to + increased user frustration. + + The probability of failure during the process of resolving an N-link + A6 chain also appears to be roughly proportional to N, since each of + the queries involved in resolving an A6 chain has roughly the same + probability of failure as a single AAAA query. + + Last, several of the most interesting potential applications for A6 + RRs involve situations where the prefix name field in the A6 RR + points to a target that is not only outside the DNS zone containing + the A6 RR, but is administered by a different organization entirely. + While pointers out of zone are not a problem per se, experience both + with glue RRs and with PTR RRs in the IN-ADDR.ARPA tree suggests that + pointers to other organizations are often not maintained properly, + perhaps because they're less susceptible to automation than pointers + + + +Expires 1/September/2002 DNSEXT [Page 3] + +INTERNET-DRAFT Representation of IPv6 addresses in DNS. March 2002 + + + within a single organization would be. + +2.2 Recommended standard action + + Based on the perceived consensus, this document recommend that RFC + 1886 stay on standards track and be advanced, while moving RFC 2874 + to Experimental status. + +3 - Bitlabels in the reverse DNS tree + + RFC 2673 defines a new DNS label type. This was the first new type + defined since RFC 1035[RFC1035]. Since the development of 2673 it has + been learned that deployment of a new type is difficult since DNS + servers that do not support bitlabels reject queries containing bit + labels as being malformed. The community has also indicated that this + new label type is not needed for mapping reverse addresses. + +3.1 Rationale + + The hexadecimal text representation of IPv6 addresses appears to be + capable of expressing all of the delegation schemes that we expect to + be used in the DNS reverse tree. + +3.2 Recommended standard action + + RFC 2673 standard status is to be changed from Proposed to + Experimental. Future standardization of these documents is to be done + by the DNSEXT working group or its successor. + +4 DNAME in IPv6 reverse tree + + The issues for DNAME chaining in the reverse tree are substantially + identical to the issues for A6 chaining in the forward tree. + Therefore, in moving RFC 2874 to experimental, the intent of this + document is that use of DNAME RRs in the reverse tree be deprecated. + + + + + + + + + + + + + + + + +Expires 1/September/2002 DNSEXT [Page 4] + +INTERNET-DRAFT Representation of IPv6 addresses in DNS. March 2002 + + +5 Acknowledgments + + This document is based on input from many members of the various IETF + working groups involved in this issues. Special thanks go to the + people that prepared reading material for the joint DNSEXT and + NGTRANS working group meeting at the 51st IETF in London, Rob + Austein, Dan Bernstein, Matt Crawford, Jun-ichiro itojun Hagino, + Christian Huitema. Number of other people have made number of + comments on mailing lists about this issue including Andrew W. + Barclay, Robert Elz, Johan Ihren, Edward Lewis, Bill Manning, Pekka + Savola, Paul Vixie. + +6 - Security Considerations: + + As this document specifies a course of action, there are no direct + security considerations. There is an indirect security impact of the + choice, in that the relationship between A6 and DNSSEC is not well + understood throughout the community, while the choice of AAAA does + leads to a model for use of DNSSEC in IPv6 networks which parallels + current IPv4 practice. + + +7 - IANA Considerations: + + None. + +References: + +[RFC1035] P. Mockapetris, ``Domain Names - Implementation and + Specification'' STD 13, RFC 1035, November 1987. + +[RFC1886] S. Thompson, C. Huitema, ``DNS Extensions to support IP + version 6'', RFC 1886, December 1995. + +[RFC2673] M. Crawford ``Binary Labels in the Domain Name System``, RFC + 2673, August 1999. + +[RFC2874] M. Crawford, C. Huitema, ``DNS Extensions to Support IPv6 + Address Aggregation and Renumbering'', RFC 2874, July 2000. + +[RFC3152] R. Bush, ``Delegation of IP6.ARPA'', RFC 3152 also BCP0049, + August 2001, + +[Tradeoff] R. Austein, ``Tradeoffs in DNS support for IPv6'', Work in + progress, draft-ietf-dnsext-ipv6-dns-tradeoffs-xx.txt, July + 2001. + + + + + +Expires 1/September/2002 DNSEXT [Page 5] + +INTERNET-DRAFT Representation of IPv6 addresses in DNS. March 2002 + + +Editors Address + + Randy Bush + Alain Durand + Bob Fink + Olafur Gudmundsson + Tony Hain + +Full Copyright Statement + + Copyright (C) The Internet Society (2002). All Rights Reserved. + + This document and translations of it may be copied and furnished to + others, and derivative works that comment on or otherwise explain it + or assist in its implementation may be prepared, copied, published + and distributed, in whole or in part, without restriction of any + kind, provided that the above copyright notice and this paragraph are + included on all such copies and derivative works. However, this + document itself may not be modified in any way, such as by removing + the copyright notice or references to the Internet Society or other + Internet organizations, except as needed for the purpose of + developing Internet standards in which case the procedures for + copyrights defined in the Internet Standards process must be + followed, or as required to translate it into languages other than + English. + + The limited permissions granted above are perpetual and will not be + revoked by the Internet Society or its successors or assigns. + + This document and the information contained herein is provided on an + "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING + TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING + BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION + HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF + MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE." + + + + + + + + + + + + + + + + +Expires 1/September/2002 DNSEXT [Page 6] +