[Top] [All Lists]

Re: [ietf-smtp] Address transformations

2016-07-31 13:32:19
I think we all agree that was a mistake, and CNAMEs are fine
in MAIL and RCPT and you shouldn't mess with them, but I can't
find any place this advice has been explicitly deprecated.

Try Section 2.3.5 of RFC 5321 (or its predecessor in 2821, which
was a tad less explicit):

this particular case.  YMMD, in which case specific suggestions
for what needs to be fixed and how to fix it would be welcome.

Putting on my nitpicky lawyer hat, I note that RFC 1123 is a full standard. RFC 2821 is a proposed standard obsoleted by RFC 5321 which is a draft standard which updates but does not obsolete 1123.

So my reading is that while 5321 tells me that it's OK to use a CNAME in MAIL FROM/RCPT TO, 1123 still tells me that it's better to resolve those CNAMEs first.

I hope that nobody who matters believes this, but if you look at the two documents it's not a totally ridiculous way to reconcile them. Should we open up 5321 again, I think a sentence specifically revoking the CNAME advice in 1123 wouldn't hurt.


ietf-smtp mailing list