Greylisting works with MPP and Postfix systems, and is integrated on a per group or system wide basis – and is another way that the MPP engine enables mail admins to reduce end user spam email even more.

We initially ran MPP with SpamAssasin, a free anti spam engine that worked well, but would only get about 60-70% of the spam coming in (which was a major improvement over 0% which is what it was!).

We then looked at upgrading to a commercial engine – and went with Mailshell. Another major upgrade, which got us up to about 85% stoppage, but with a few emails starting to get false positives. Its always going to happen thanks to the many and varied ways spammers try to get their junk out!

Just recently we went to one of the premium anti spam engines (Cloudmark being the other one) called Commtouch. And i have to say the spam recognition is now around 96-98%, with virtually NO false positives! Our customers are getting the advantage of only real mail coming in, and our mail server is not overloaded with junk. It only costs a few dollars more per year for each mailbox to have the premium engine, but it was worth every cent. It is becoming a strange expenrience to check the mail each day and find its all real – something I havent seen in a real long time!