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Re: RFC2821bis-01 Issue 12: IPv6 MX records and transitions

2007-04-11 17:38:46

At 12:09 11-04-2007, Frank Ellermann wrote:
Strictly speaking it's not allowed to use <some(_at_)thing(_dot_)local>
in Internet messages or SMTP envelopes in the public Internet
as defined by STD 10, because we have no way to send a reply
or error report to <some(_at_)thing(_dot_)local> if we're not in the
same local net.


There MUST be a gateway fixing this before it reaches us.  If
not it's a standards violation.  Very likely it's also spam


IPv6 only addresses are not better than UTF8SMTP addresses,

UTF8SMTP is a SMTP extension. The main issue with IPv6 is reachability which a SMTP extension won't solve.

For starters the MAIL FROM has to work.  That's essential for
SMTP.  And it's enforced by receivers employing some kind of
"call back verification".  Even if it's as little as checking
that the domain in question has an associated IPv4 address.

And a plausible (receiver's POV) MAIL FROM isn't enough, the
end user getting the mail would also like to click a "reply"
button, expecting that the Reply-To (or From) address work.

Interestingly, one might read "alternate address functions" and "intermediate relays" as a means to get the above working.

There can be numerous cases where it won't work in practice,
that's just the "S" in SMTP, but if it systematically doesn't
work it's a violation of the spec.

Prohibiting "IPv6 only" would get this draft shot down. I don't think we want that to happen.