MX/AAAA problems

[Alain Durand]

On Apr 29,  8:36am, Bob Fink wrote:
> Subject: Re: MX/AAAA problems
> Thanks for the explanation.  Does anyone have a clue as to the pathology of
> the failure in dns code (or wherever) so we can blow a whistle on this
> quick?

>From what we have seen, some DNS server are really picky. When they
see unusual RR, they think the entry is either tainted or invalid.
Some old secondary servers seeing AAAA records think the whole zone
is invalid and refuse to tranfer it.
That's the main reason why we choose to use a separate subdomain ipv6.foo.tld
to store AAAA records.

But then, there is another problem. How do you choose the outgoing E-mail
address if you use the ipv6.foo.tld subdomain ? Should it be
user@host.foo.tld or user@host.ipv6.foo.tld ?

If you choose user@host.foo.tld, relpies will not use IPv6 but IPv4 instead.
If you use user@host.ipv6.foo.tl and the mail is relayed later to an IPv4 MTA
then, you end up with the same problem, this host may crash when it sees
a AAAA record. :-(

The ipv6 subdomain trick is only a short term patch. Hopefully people
will upgrade to more recent releases of bind soon enough.

	- Alain.