BIND 9 AAAA record problems

[JINMEI Tatuya / 神明達哉]

>>>>> On Mon, 28 Jun 2004 14:55:32 +0000, 
>>>>> "Todd T. Fries" <todd at fries.net> said:

> Why is it a bad thing to start out with AAAA?  Proper getaddrinfo()
> implementations should query first an AAAA then an A record for names,
> so that applications can then connect to whatever is appropriate.

> It is all part of a `seamless' transition to v6 that has started, albiet
> slowly.

> For whatever it is worth, the libc in OpenBSD behaves this way, and I
> quite am pleased that it does.

> It's not a bug, it's a feature ;-)

In general and in theory, I agree.  But we should also note some
practical issues in the real world.  To name a few:

- there are some misbehaving authoritative servers against AAAA
  queries.  See draft-ietf-dnsop-bad-dns-res-02.txt for more details.

- I've noticed some applications do not implement the proper fallback
  mechanisms from IPv6 to IPv4.  Some do not fall back to A queries
  when AAAA queries fail (with "NONAME").  Some do not try to connect
  the IPv4 addresses when the attempt to connect to the IPv6 addresses
  fails.  I see mozilla/firefox show this behavior with its internal
  resolver routines.

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					jinmei at isl.rdc.toshiba.co.jp