MailScanner is a generic scanner for use by MTAs, intended to drive a spam filter and a virus scanner. It is written in Perl and can be set up with at least 
Sendmail and Exim.
It usually comes packaged for use with the SpamAssassin spam filter. Plug VipulsRazor into SpamAssassin and ClamAv into MailScanner, and you have a complete Free anti virus and spam proxy solution - always a good thing to put equip an enterprise mail server with.
See also
7 pages link to MailScanner:
