MX/AAAA problems

[Bob Fink]

Rich,

At 5:25 AM -0700 4/29/97, W. Richard Stevens wrote:
>I have been having intermittent email problems for the past months
>that I have finally tracked down.  Most hosts could send email to my
>kohala.com domain without a problem, but a few had continual problems.
>
>I have finally tracked the problem down to an MX record that points to
>a host with a AAAA record.  The MX record was the one with a higher
>preference, and it was never used, but just the presence of a AAAA
>record for that host causes some mailers/nameservers to gag (and say
>the domain is unresolvable).  The AAAA record was being returned by
>my nameserver as additional records for either an ANY query or an MX
>query.  mcimail.com and mail12.digital.com are two of the servers
>that could not send me email.
>
>This is just a warning to others on the 6bone to avoid this problem.
>I know many sites are placing all the AAAA records into a separate
>.ipv6 subdomain, which solves the problem (or at least makes it a
>local problem), but at some point more of these AAAA records that
>older servers cannot grok are going to filter up.

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?


Bob