Glenn Steen glenn.steen at
Mon Sep 25 22:14:25 IST 2006

On 25/09/06, John Rudd <jrudd at> wrote:
> Glenn Steen wrote:
> > Just a small observation: I see that you (IMO rightly) reject the
> > domain literal (MX IP address) too... This _technically_ breaks RFC
> > compliance.
> There was just a discussion about this over on the mimedefang mailing list.
> What the RFC (2821?) prohibits is rejection based on the HELO/EHLO given
> hostname not resolving to the IP address of the submitter.
> You can reject for other reasons.  Like they gave you your own domain
> name.  Or your own IP address.  That's rejecting for a different reason
> than "the IP address and Hostname don't match".  As long as the reason
> isn't literally "I looked up the name they gave me in the Helo, and it
> didn't resolve to the IP address I'm talking to".
> Them giving you your own hostname, of course, is logically the same as
> them giving you a hostname that doesn't match their IP address, but your
> reason for rejecting it is "it's _MY_ hostname", so that doesn't violate
> the RFC prohibition.
Yes, that is exactly why it is a good idea. Either a case of bad
memory on my part then, or simply a case of 2821 superseding some
other rfc that I have this dim recollection of:-).

-- Glenn
email: glenn < dot > steen < at > gmail < dot > com
work: glenn < dot > steen < at > ap1 < dot > se

More information about the MailScanner mailing list