Previously my own anti spam mail server solution has been replaced by Ironport, an all-in-the-box-anti-spam-appliance. It doesn't look bad, it makes its job and its easier to administrate than postfix, amavis, spamassassin, etc. But... it costs much much more. So does that mean it fights spam better?

As soon as the MX entries were switched, I compared the amount of incoming spams on two public folders (shared mailboxes). The e-mail addresses of these mailboxes are shown on the Internet, so they get a lot of spam. But with which anti-spam-solution will there be more spam?

Take a look at the following graphical statistics (the day of the switch was July 29):

MX represents the Open Source Anti-Spam mail server (Postfix with Postgrey greylisting and RBL and HELO checks, Amavisd-new with ClamAV, SpamAssassin and Quarantine).

The first mailbox on the left received an average of 8 spams per day. After the switch to Ironport there were an average of 17.3 spams per day.
An increase of 116%!

The second mailbox had an average of 16.5 spams per day in the mailbox, compared to 39.5 with Ironport.
Increase of 139%!!

However be careful with this comparison. If you want to use Open Source as your anti-spam mail gateway, you sure need to know what you're doing, how to install, configure and bundle all the different elements together. But if the right knowledge is there, one can easily beat anti spam appliances.