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.
Take a look at OpenProtect, which integrates MailScanner, SpamAssassin and ClamAV into an easily installable bundle.
See also
7 pages link to MailScanner:
MailScanner