Re: [Exim] CNAME and recipient rewriting

Philip Hazel wrote:
>
> Without checking,[1] I seem to recall that this is something that was in
> earlier RFCs and which Sendmail implemented. However, a lot of other
> MTAs (including Exim) do not do this, and nowadays it is not seen as the
> "right thing to do". So it is not present in RFC 2821.

I can't find it in 2821 either but I'm not sure what 'updates' in RFCs
mean, so I can't be sure about 2821 invalidating the paragraph below
from 1123.

> [1] Hmm. Can't find it in 821 or 1123.

rfc1123:

5.2.2 Canonicalization: RFC-821 Section 3.1

The domain names that a Sender-SMTP sends in MAIL and RCPT
commands MUST have been "canonicalized," i.e., they must be
fully-qualified principal names or domain literals, not
nicknames or domain abbreviations. A canonicalized name either
identifies a host directly or is an MX name; it cannot be a
CNAME.

endre