Microsoft Exchange Server - Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft.
Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
hMail Server - hMailServer is a free e-mail server for Microsoft Windows.
Sendmail - Sendmail is a general purpose internetwork email routing facility that supports many kinds of...
Zimbra - Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.
Exim - Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.