SpamAssassin in a Box is a powerful and reliable spam filter for Windows. Beside the famous e-mail filter SpamAssassin, it also contains a Windows system service, making SpamAssassin controllable via the Windows Service Control Manager.
SpamArrow is a SpamAssassin based spam blocker to effectively filter unwanted spam emails with near zero false positives. This anti spam software is a great add-on for Outlook and Outlook Express by automatically creating integrated toolbar buttons.
SMTP proxy server based spam filter that sits between the internet and your mail server. Incoming mail is accepted from the open internet, checked for spam, and is then delivered to your existing SMTP mail server. Freeware for non commercial use.
VirusCop is a simple freeware Windows program for reporting virus spam, erroneous e-mail bounces and other spam. It allows you to paste in the headers from virus spam and the relevant ISP e-mail contacts.
Connects POP3/IMAP accounts to a SMTP or Exchange mail server. Runs as system service in the background. An easy to use config tool allows you to manage you accounts. A Spam filter, a powerful rules engine and virus scanner integration are included.
GateWall Antispam is a mail gateway solution with integrated spam filtering and antivirus tools. GateWall Antispam supports all the leading spam filtering technologies and features Cloud Antispam and Bayesian statistical spam filtering.
CleanMail is a complete SMTP/POP3 email security solution (Anti-Spam/Anti-Virus) that works with any mail server like Microsoft Exchange 2003/2007/2010, Microsoft Small Business Server (SBS) 2003/2008, Lotus Notes/Domino or IMail.