Chris Cameron wrote:
I have a Postfix server that sits in front of Exchange. Exchange has
anti-spam software running that will reject what it deems as spam.
This is creating a problem for Postfix, which accepts a message, and
tries to send it to Exchange, who then rejects it. That leaves Postfix
with an email it has to try to bounce to a (usually) non-legitimate
sender.
It'd be nice if Exchange accepted and then silently dropped, but that
doesn't seem to be coming. So, on my part, what can I do with Postfix
to drop messages that Exchange (defined through the transport file)
rejects?
Exchange is accepting mail, then rejecting it, which is a problem with
Exchange, not Postfix.
Anything you do with Postfix to delete the rejected mail that Exchange
as already accepted will also lose legitimate mail Exchange thinks is spam.
The recipient will not get the mail and the sender will not get a reject
notice, which breaks the integrity of the SMTP protocol and will really
annoy a lot of people.
My suggestion would be to:
* Do the spam processing on or before the postfix box and turn it off on
exchange, or
* Configure Exchange to deliver spammy mail and just mark it as spam.
Any solution that accepts mail and them bounces it later will make you a
bounce-back spam source and get your servers blacklisted. Any solution
that accepts mail and deletes it will have the users at your door with
pitchforks and torches.
Terry
