[exim] Re: Exim hates CNAMEs, not IPv6

Góra strony
Delete this message
Reply to this message
Autor: Andreas Metzler
Data:  
Dla: exim-users
Temat: [exim] Re: Exim hates CNAMEs, not IPv6
On 2023-12-01 John R Levine via Exim-users <exim-users@???> wrote:
> It appears that Jeremy Harris via Exim-users <jgh@???> said:

[...]
> > Our log says that message was aimed at exim-users@???


> Oh, I see the problem. lists.exim.org is a CNAME for cumin.exim.org,
> and qmail is standard compliant per RFC 1123:


>       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.


> When I put in an explicit route it uses that rather than resolving the CNAME,
> unrelated to IPv6.


> It's poor form to use a CNAME as a mail domain, and worse form not to
> do what the standard says, but I suppose that horse left the barn a
> long time ago.


Hello,

Afaict this part of rfc1123 has been superseded by RFC 2821 [1] anno 2001
which explicitely allows CNAMES.

cu Andreas

[1] since superseded by rfc 5321

--
## subscription configuration (requires account):
## https://lists.exim.org/mailman3/postorius/lists/exim-users.lists.exim.org/
## unsubscribe (doesn't require an account):
## exim-users-unsubscribe@???
## Exim details at http://www.exim.org/
## Please use the Wiki with this list - http://wiki.exim.org/