Anti Spam Software for a Send Mail Relay
 

We use sendmail to relay our email from the dmz to our Exchange server.
We use the anti spam option in send. So we use domain blacklist.
But this is not enouth. We need a content filtering.
Is it something like that for sendmail....???
I want the filtering to be made directly on the relay(sendMail).
Any Idea?

Amavis, SpamAssassin, or search Freshmeat like http://freshmeat.net/search/?q=sendmail+filter or http://freshmeat.net/search/?q=spam&section=projects