[Mimedefang] filter-relay, rejection on bogus helo

[David F. Skoll]

On Tue, 6 Jan 2004, Lucas Albers wrote:

> General question,
> Is it reasonable to expect if $helo and $name are ip addresses, that they
> should match?

Not necessarily.  The sending host could be behind a NAT box, and might not
know its externally-visible IP address.

However, $helo should *never* be just a plain IP address.  If a host wants
to use an IP address literal, it's supposed to enclose it in square
brackets.  For example:

	HELO 192.168.1.1           is BAD
	HELO [192.168.1.1]         is OK

I reject hosts that use plain IP addresses, and haven't had any complaints.
(Note, however, that no MUAs connect to our inbound server; only other
MTAs.)

Regards,

David.