XamimeLT give to you the ability to block or pass email based on any set of tests you choose, varying from virus scans to email text content. XamimeLT can do this because it unpacks all email sent through it in such a way that normal UNIX tests can be performed to determine the nature of the email.

http://www.pldaniels.com/xamimelt

-- LucaGibelli - 11 Feb 2007