[ On Monday, June 30, 2003 at 17:19:42 (-0400), Troy Settle wrote: ]
> Subject: RE: Now well off-topic - was Re: [Exim] how to configure HELO/EHLO and DNS for multi-homed hosts
>
> My overpriced mail server sends HELO/EHLO of 'psknet.com' which is what I
> defined as the parimary_hostname in the exim configuration. This is
> innaccurate, however, as 'psknet.com' is currently on a machine that does
> not listen for incoming SMTP traffic. No biggy though, it's a FQDN, it
> resolves forward and backward, and has appropriate MX records in place.
Actually it is a "biggy".
Your SMTP server, when acting as a client-SMTP, is required to ("MUST")
use a canonical host domain name that will resolve back to the IP
address its outbound connection originates from.
Your mail server is lying about its identity.
> Here's what it looks like:
>
> Received: from kennedy.psknet.com ([63.171.251.9] helo=psknet.com)
$ host psknet.com
psknet.com A 63.171.251.4
63.171.251.4 does not match 63.171.251.9
Your received header example proves that your mailer is lying about its
identity. (your received header example is also incorrectly formatted
as per the rules defined in RFC 2821 :-)
It is irrelevant that your server happens to use the same name as the
parent zone of the PTR its actual address resolves to. Sub-domain games
are not allowed -- only fully qualified canonical host domain names (or
address literals) may be used, and they "MUST" resolve to an A record
matching the client address.
Also, MX records are irrelevant for the greeting name.
--
Greg A. Woods
+1 416 218-0098; <g.a.woods@???>; <woods@???>
Planix, Inc. <woods@???>; VE3TCP; Secrets of the Weird <woods@???>
