--On Wednesday, 26 March, 2008 17:09 +0000 Tony Finch
With that change to "address record", if no MX record is
found, the SMTP client is required to look for DNS names with
either A or AAAA RRs, rather than A RRs only.
There's also RFC 3974 (Jan 2005, informational) which
recommends treating AAAA like A. The most popular MTAs
implement this logic.
Yep. But the people who are already convinced that treating
AAAA like A is the Right Thing are, well, already convinced.
And those who aren't will probably just say "well, 3974 is
Please see comments (yours, mine, and others) on the ietf-smtp
IETF mailing list