Scalix - Enterprise-class email & group calendaring based on Linux. Scalix Collaboration Platform is the field-proven, commercial-grade email platform that forms the base of all our product editions. You can try it out in our free Community Edition or you can get the source code. It is an industrial-strength platform with email, group calendaring, contacts, tasks, and shared public folders. Supports Outlook, Evolution and any POP/IMAP client.

Features :-

1. Scalix email and calendar server, a full-featured messaging and collaboration server based on Linux and open source.
2. ScalixConnect for Outlook, robust third-party native and transparent Outlook support.
3. Scalix Web Access, an AJAX-based cross-browser, cross-platform email and calendaring client that combines desktop email functionality with the convenience of a browser.
4. ScalixConnect for Evolution, full-function email and calendaring client support for Linux desktop users.
5. Scalix Wireless Solution, advanced wireless email/PIM support for Blackberries, Treos and Smartphones.
6. Scalix Administration Console, AJAX-based web client for administering the Scalix server and email users.
7. ScalixReady for Open Source and Commercial messaging ecosystem components, which certifies that third party software works with Scalix.
8. MS Ecosystem Interoperability for seamless co-existence with MS Exchange and Active Directory.
9. Individual email level backup / restore when using SepSesam.

It was based on HP OpenMail, which was licensed from Hewlett Packard. It provides e-mail, calendars and other collaborative software, which are standard in groupware. It can be accessed from many different clients, most notably Microsoft Outlook, Novell Evolution (formerly Ximian) and Scalix Web Access, an AJAX-based web email and calendaring client that combines the functionality of desktop email with the ease-of-use of a browser.