Subject: RFC 3484, was Re: Unexpected AAAA queries
To: Thomas Seeger <>
From: Frederick Bruckman <>
List: tech-net
Date: 07/13/2003 13:57:57
On Sun, 13 Jul 2003, Thomas Seeger wrote:

> >> While using NetBSD on an i386 machine I experience large delays in
> >> http/ftp/etc. connections:  [...tcpdump showing AAAA queries...]
> > The resolver library is trying to do IPv6 lookups.  (It
> > doesn't realize, at this point, that it can't do v6 connections, and
> > indeed, I'm not sure it should; it's perfectly reasonable to do a v6
> > address lookup on a v4-only host.)
> > I'd be more inclined to address the question of why they're
> > going unanswered.  What DNS server are you using?
> The DNS server on bummi is WinRoute 4.2, configured as a caching forwarder.

How fast does your host connect to or
If it's no better, it means that the slowness you experience is not
that the AAAA lookups are happening in the first place, but rather,
that the ultimate connect attempt tries the IPv6 addresses first, then
has to wait for them all to fail before getting to the IPv4 address.

The solution to that other problem is to implement RFC 3484, in
particular, to permit a site-specific policy table that orders the
results of getaddrinfo() (to place, in this case, IPv4/IPv4-mapped
addresses first). Anyone know how close KAME is to doing that?