FTGate 5.0
FTGate is a powerful Windows(TM) mail server suite that combines exceptional mail handling facilities with comprehensive Groupware functionality. FTGate features include SMTP, POP3, calendaring, contacts, IMAP, enhanced security, advanced anti-spam facilities, anti-virus support, multiple domains, Web Administration, WebMail, instant messaging, SSL, SPF and much more.

ORF Enterprise Edition 4.2
ORF Enterprise Edition is an enterprise-level anti-spam solution that helps you to block spam before it reaches your network. ORF uses a combination of anti-spam technologies and custom filtering options to stop the spam on SMTP protocol level. ORF can be used with Windows 2000's/2003's built-in IIS SMTP Service and Microsoft Exchange Servers (2000, 2003 or 2007)

VisNetic MailServer 9.1
VisNetic Mail Server is a versatile multi-featured mail server for Windows operating systems. VisNetic Mail Server can be licensed for any size organization as well as ISP and ASP environments. VisNetic Mail Server combines a simple, easy-to-use administration console with unmatched mail server security, speed, and scalability. VisNetic Mail Server features support for Sender Policy Framework (SPF) and Spam URI Realtime Blocklists (SURBL).

Antispam Marisuite for Outlook 1.0.6
Antispam Marisuite is embeddable tool for Office Outlook. It checks each incoming message and moves spam to Junk E-Mail folder. Messages, which cannot be filtered without your assistance, are moved to Quarantine folder. Available wizard takes care of initial configuring and training the spam filter so application begins work effective right after installation. Antispam Marisuite is trainable so anything you consider spam will be treated as spam.