added section about zone transfer protocol interoperability issues

doc/misc/migration

@@ -109,6 +109,8 @@ name is deprecated.  Use \$ instead.
 
 3. Interoperability Impact of New Protocol Features
 
+3.1. EDNS0
+
 BIND 9 uses EDNS0 (RFC2671) to advertise its receive buffer size.  It
 also sets an EDNS flag bit in queries to indicate that it wishes to
 receive DNSSEC responses; this flag bit usage is not yet standardized,
@@ -126,6 +128,19 @@ authoritative servers use this server will be very slow or fail
 completely.  We have contacted the manufacturer of the name server in
 case, and they are working on a solution.
 
+3.2. Zone transfers
+
+Outgoing zone transfers now use the "many-answers" format by default.
+This format is not understood by certain old versions of BIND 4.  
+You can work around this problem using the option "transfer-format
+one-answer;", but since these old versions all have known security
+problems, the correct fix is to upgrade the slave servers.
+
+Some BIND 9 users have reported interoperability problems with zone
+transfers to Microsoft DNS servers that were solved by specifying
+"transfer-format one-answer;", but we are still lacking detailed
+information about this issue.
+
 
 4. Unrestricted Character Set
 
@@ -185,4 +200,4 @@ directing queries for a given domain to a particular set of name
 servers.
 
 
-$Id: migration,v 1.28 2001/03/27 23:59:53 bwelling Exp $
+$Id: migration,v 1.29 2001/04/25 17:35:10 gson Exp $