If you’re looking to run a serious open source collaboration server, Yahoo’s Zimbra Collaboration Suite (ZCS) should be on your short list. This Web 2.0 email and groupware server offers AJAX Web-based administrator and user interfaces, a variety of useful groupware features, and email import functionality.
ZCS comes in five versions. The Open Source Edition, which is the one I tried, doesn’t have all the features of the others, but it’s purely open source.
Zimbra claims all the editions run on Mac OS X and a variety of Linux platforms, including Red Hat Enterprise Linux (RHEL), Fedora, Ubuntu, Debian, Mandriva, SUSE Linux Enterprise Server (SLES), rPath (a software appliance ISO image), and VMware (a certified virtual appliance). I installed ZCS 5.0.20 on both openSUSE 11 and SLES 10 SP2.
Installation was a breeze, and that’s something I rarely say about serious server applications. Zimbra uses a single staged installation to install all its multiple parts. Like many Unix and Linux applications, Zimbra actually incorporates multiple applications. It uses Apache Tomcat for the Web application server, Postfix for the mail transfer agent (MTA), Clam AntiVirus for virus scanning, SpamAssassin and DSPAM for spam filtering, OpenLDAP for user authentication, and MySQL for user preferences and the message data store. You could install all those by hand, but who would want to?