IPv6 woes - RFC

Wed Sep 8 20:07:40 UTC 2021

It appears that Bill Woodcock <woody at pch.net> said:
>> The next thought was SMTP
>
>I assume someone’s tried using MX record precedence to do this?  AAAA record references with lower values than A record references,
>and see what happens?  Anyone have any results to share there?

I used to publish two MX records at the same precedence, one with an A record
and one with an AAAA record.  It didn't work very well because some v4 only
systems decided that an MX without an A record meant my mail system was
broken.  Now I have one MX with both which works OK.

Postfix has some parameters to say whether to prefer v4 or v6 at the same
priority.  Wietse says don't prefer v6, you'll lose mail.

R's,
John