Hi,

> > 1) That the IP address of the connecting server is in the list of IPs
> > returned by DNS A and MX RR of the name given in HELO/EHLO.
>
> FWIW it is hard to get sendmail to put in the address of the interface
> on which the email is beig sent.  The address of its main interface
> may not be in a publically visible DNS (eg if it is a 192.168.x.x address)
> Doing so (look at the headers for this mail) means that the systems
> actual name is completely absent.

Actually, that's really easy:
O DaemonPortOptions=Family=inet, address=0.0.0.0, Name=MTA
O DaemonPortOptions=Family=inet6, address=::, Name=MTA6, Modifiers=O
#O ClientPortOptions=Address=0.0.0.0

If a server tells me that it's address is 192.168.something, I certainly
do want to drop that server's email as spam.

> Checking for the MX record (ie requiring that the outbound mail gateway
> is the same is the inward one) will surely lead to incorrect bounces.

That's why I don't want to do that. I want to check A AND MX records; the
name which is given should be a working address in one of the two sets of
addresses.

Any ideas on how?

Thanks,
John Klos
Sixgirls Computing Labs