ePrism is an email filter and spam filtering appliance that provides organizations with a total secure email perimeter defense solution. [Hardware]

Explains how to build a Debian anti-spam and anti-virus gateway E-mail server using Postfix, amavisd-new, SpamAssassin, Razor, DCC, Pyzor and ClamAV.[Unix]

A very effective anti-spam appliance. MailFoundry creates a spam firewall for effectively stopping spam. [hardware]

Challenge/response system. Multi-platform filtering free software written on Python. WLE requires a confirmation from unknown senders before delivering their mail in your mailbox. [Unix]

MailStripper is an SMTP-level spam filter with antivirus capability for Linux, FreeBSD and Solaris. [Unix]

JSpamFilter is Java-based, performs both source and content filtering, and provides a variety of treatment options. It is high-performance and highly customizable. [Java]

Anti-spam software that filters spam, viruses, web bugs, and phishing scams. Eliminates unwanted junk e-mail from corporate servers. [Windows]

Spam control using Blacklists, mark spam by modifying subject, anti relay possibilities. [Windows]

Advanced E-mail proxy incorporating Spamassassin. [Windows]

The PowerElf II anti-spam appliance uses several different techniques to help stop spam at its entry point, before it has a chance to travel to the end-user's mailbox. [Hardware]