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.

PlexMailer 6.5
PlexMailer is an anti-spam software. It supports POP3, IMAP, LDAP, NNTP and MBOX protocols. It comes with dozens of filters such as Bayesian Filter and ORBS, MAPS and DUL. Also, it supports server side options and integration with other products.

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).

MailScan for Mail Server 5.5
MailScan 5.5 is the world's most advanced Real-Time AntiVirus and AntiSpam solution for Mail Servers. The software safeguards organizations against Virus, Worm, Trojan and many other malware breeds with futuristic and proactive technologies. Employing an array of intelligent filters, MailScan offers powerful protection against Spam and Phishing mails, while providing comprehensive Content Security too. To know more, visit http://www.mwti.net