MailScanner is a virus and spam scanner for e-mail designed for use on e-mail gateways.
Not only can it scan for known viruses, but it can also protect against unknown viruses hidden inside e-mail attachments by refusing entry to attachments whose filenames match any given pattern. This can include generic patterns that trap filenames attempting to hide the true filename extension (e.g. ".txt.vbs").
It is easy to install into an existing e-mail gateway, requiring very little knowledge of sendmail and no change to an existing sendmail configuration.
This version is for RedHat, Fedora and Mandrake Linux (and other RPM-based Linux distributions).