Open Source Email Servers

NethServer 7 is an operating system for Linux enthusiasts, designed for small offices and medium enterprises. Based on CentOS, the product's main feature is a modular design which makes it simple to turn the distribution into a mail server and filter, web server, groupware, firewall, web filter, IPS/IDS or VPN server. A comprehensive web-based user interface simplifies common administration tasks and enables single-click installation of several pre-configured modules. Stay tuned with NethServer 8! Follow the links on http://www.nethserver.org for more information

Collabsuite is an open source mail and collaboration software which is highly integrated and cost-effective. It provides comprehensive Linux mail server with calendaring and instant messaging functionality for enterprise. With all its high-end functionality, it is a great alternative to MS Exchange and other proprietary and expensive solutions. The Server is built on GNU/Linux Debian and makes use of various free software such as Postfix, Dovecot, Ejabberd, Darwin Calendarserver and SOGo. The Webclient is based on the popular Roundcube webmail software, while the Archiver is based on the open source edition of Mail Archiva and is bundled with the Dojo Toolkit for the Chat Archive Interface.

Spicebird is an open-source email and collaboration suite based on the Mozilla platform. It provides integrated e-mail, contacts, calendaring and instant messaging. It can connect to any SMTP/IMAP email server, CalDav Calendar server and Jabber serve