======Mail Servers=====

=====Free=====
[[http://cyrusimap.web.cmu.edu/|Cyrus IMAP]] (License: [[http://cyrusimap.web.cmu.edu/mediawiki/index.php/Downloads#Licensing|BSD style]]) \\
[[http://www.dovecot.org/|Dovecot]] IMAP en POP3. (License: [[http://www.dovecot.org/doc/COPYING|LGPL 2.1 and others]]) \\
[[http://www.dbmail.org/|DBMail]] IMAP and POP3. [[http://git.dbmail.eu/paul/dbmail/|git repository]]. (License: GNU GPL v2) \\
[[http://www.courier-mta.org/|Courier Mail Server]] (License: GNU GPL) \\

[[http://www.openchange.org/|OpenChange]] is a portable Open Source implementation of Microsoft Exchange server and Exchange protocols. It provides a complete solution to interoperate with Microsoft Outlook clients or Microsoft Exchange servers. (License: GNU GPL v3)\\

[[http://www.hmailserver.com/|hMailServer]] is a free e-mail server for Microsoft Windows. \\

[[http://www.vergenet.net/linux/perdition/|Perdition]] is a fully featured POP3 and IMAP4 proxy server. It is able to handle both SSL and non-SSL connections and redirect users to a real-server based on a database lookup. (License: GNU GPL) \\

[[http://www.greatcircle.com/firewalls/mhonarc/firewalls.199707/msg00505.html|Obtuse smtpd/smtpfwdd]] (development stopped in 1997) \\
[[http://c0re.23.nu/c0de/osmtpd/|osmtpd]] based on Obtuse smtpd 2.0 \\

[[http://tiswww.case.edu/php/chet/info/emm.html|Emm Mail Manager]] This is emm/sm, an electronic mail manager for Unix. Emm is very similar (by design) to the version of MM from the DEC-20, but fits smoothly into the Unix environment.

=====Commercial=====

[[http://www.axigen.com/|Axigen]] \\
[[http://www.altn.com/Products/MDaemon-Email-Server-Windows/|MDaemon Email Server software for Windows]] \\
[[http://www.mailenable.com/|MailEnable]] For Microsoft Windows. Free Standard edition available. \\
[[http://www.scalix.com/|Scalix]] Linux Email, Calendaring and Messaging Platform. Free Community Edition available. \\
[[http://www.open-xchange.com/|Open-Xchange]] // There is a free open-source edition, but it isn't easy to find it on their website, so I'm listing it under Commercial. // \\
[[http://www.zimbra.com/|Zimbra]], also provides an [[http://www.zimbra.com/downloads/os-downloads.html|Open Source Edition]] \\