Free suite software for linux

StatsDawg is a suite that has been designed to be easily usable as well as configurable.

StatsDawg monitors various aspects of a Linux system such as CPU usage, load average, memory usage, etc. using RRDTool and PHP.

phpGroupWare is a multi-user groupware suite written in PHP.
It provides about 50 web-based applications, as there are the Calendar, Addressbook, an advanced Projects manager, Todo List, Notes, Email, Newsgroup- and Headlines Reader, a Filemanager and many more Applications. The calendar supports repeating events and includes alarm functions. The email system supports inline graphics and file attachments.
The system as a whole supports user preferences, themes, user permissions, multi-language support and unser groups. It includes modules to setup and administrate the working environment. The groupware suite is based on an advanced Application Programming Interface (API).
Enhancements:
- Security Fix for CVE-2007-4048
- Improved PHP 5 support
- Various bug fixes

Buni Meldware Communication Suite (MCS) is a platform-independent groupware package consisting of:
- Meldware Mail
- Meldware Calendar
- Meldware Webmail
- Meldware Secure Administration System
Together the package provides support for thousands of users concurrently to send and receive email and to schedule meetings. MCS uniquely allows you to store all messages and scheduling events in nearly any database and runs on nearly all popular software and hardware platforms.
MCS commitment to platform and database agnosticism aims to meet increasing business requirements to maximize ease and flexibility of managing and accessing data as well as putting a premium on interoperability.
Additionally, while the scheduling and calendaring services can be installed separately, the integrated feature set provides both a distinctive and powerful experience to both users and server-side Mail Based Applications and Collaboration Based Application Services.
The MCS platform provides security integration using LDAP sources including Microsoft Active Directory as well as flat-file and database sources.
Additionally, extensible security allows custom authentication/authorization sources.
Enhancements:
- This is the first milestone release with WCAP, freebusy for webmail, and mature IMAP all together.
- It has undergone extensive hardening, dogfooding, and QA testing.
- The WCAP protocol for calendaring now works well for Thunderbird and Lightning 0.3.
- Webmail calendaring was greatly improved.
- The abillity to download attachments has been added to the webmail interface.
- Numerous performance improvements have been made in SMTP, IMAP, and MIME parsing since 1.0-M7.

Zimbra Collaboration Suite project is a client/server technology for enterprise messaging and collaboration.
Zimbra delivers innovation for both the administrator and the end-user as well as compatibility with existing infrastructure and applications (both open source and proprietary).
The Zimbra Collaboration Suite provides support for email, contacts, and group calendaring, and consists of a server and client.
Main features:
Administrator Benefits
- Online move, backup and recovery of individual or a group of mailboxes
- Compatibility with Active Directory and existing LDAP directories
- Native hierarchical storage management and clustering
- Web services integration with existing enterprise applications
- Integrated anti-spam and anti-virus
End-User Benefits
- Browser based client with search, shared calendar and mail that is integrated with contacts and calendar
- Support for Outlook: calendar, mail, contacts and offline mode
- Support for mobile devices: Blackberry, Treo and etc
- Support of Windows, Apple and Linux computer.
Whats New in 5.0.0 Beta 1 Development Release:
- This is the first release in the 5.0.0 release cycle.
- New features include IM, Tasks, Standard Client autocompletion, and keyboard navigation.
- Updates have been made to migration wizards and apple/outlook connectors.
Whats New in 4.5.6 Stable Release:
- Support for an automated MySQL database corruption check that will send a notification to the admin.
- Spam training has been enhanced by allowing programmatic scanning of folders without requiring a password.
- Admins can get backup and restore complete notifications sent via email.
- .Doc and .pdf files open correctly in Zimbra Web Client.
- iSync will not duplicate the calendar, and iSync Connector works correctly with Mac OS X 10.4.10.
- Servers automatically start after a ZCS upgrade.
- Web-based cross-mailbox discovery is available for the optional Zimbra Archiving and Discovery module.