Hi - I'm sure someone's thought of this already or has a better idea but
here goes anyway...
Ideally MXs are set-up identically as their primaries even to the point
they know which accounts are valid so as to be able to 550 senders
before accepting anything. Unfortunately that's not always possible and
so a lot of spam can be accepted by 2-MXs which then is found upon
delivery to the 1-MX not to have a live rcpt. Result: mess.
So - much like exim does sender callbacks, could it also do 1-MX call-
forwards? Yes, of course, if a 2-MX is being contacted at all presumably
the 1-MX is unavailable. But that's often not the case with spam - they
will try all, often *preferentially* 2-MXs.
</thinking-out-loud>,
Paul
--
Paul Makepeace ................................
http://paulm.com/ecademy
"What is a mouse? Terrible."
--
http://paulm.com/toys/surrealism/