Kolab is an open source groupware solution. It consists of the Kolab server and a wide variety of Kolab clients, including KDE PIM-Suite Kontact, Horde Webfrontend, Mozilla Thunderbird and Mozilla Lightning with SyncKolab extension and Microsoft Outlook with proprietary Kolab-Connector PlugIns.
Kolab adds intelligent interaction between the components, a web administration interface, management of free-busy lists and more. Major components of the Kolab Server are OpenLDAP, Postfix, Cyrus IMAP, Apache, SASL, and OpenSSL.
It supports mixed client environments (Outlook/KDE) because of an open storage format. Any email client speaking standard protocols can be served.
Kolab2 Server uses the OpenPKG environment to provide a constant base across multiple platforms and distributions.
Key Features
- Full seamless support of mixed clients environments (Outlook, KDE, Web etc).
- Support for the K Desktop Environment with Kontact.
- Support for Microsoft Outlook with proprietary connector PlugIns.
- A web administration interface.
- Configuration data is kept in a LDAP directory.
- A global LDAP adressbook for contacts.
- IMAP4rev1 as well as POP3 access to mail.
- Full support for client-side PGP and S/MIME email encryption (officially Sphinx-interoperable).
- Full support for shared calendars with IMAP ACLs.
- Full support for shared contacts with IMAP ACLs.
- Fully offline capable using KDE Kontact or Microsoft Outlook.
- Support for server side resource management (e.g. rooms, cars).
- Full support for freebusy handling.
- Cross-Folder-Search.
- Birthday Calendar that automatically shows the birthdays of all your contacts from your address book in one neat calendar.
- Dedicated Out-of-Office settings where you can specify when you are in vacation and which message should be sent under which circumstances.
- Email tags.
- Notes.
- Folder management.
Website: www.kolab.org
Support:
Developer: The Kolab-Project and the Kolab-Konsortium
License: Various freely distributable licenses

Kolab is written in C++ and PHP. Learn C++ with our recommended free books and free tutorials. Learn PHP with our recommended free books and free tutorials.
Related Software
| Groupware Software | |
|---|---|
| Zimbra | Full-featured collaboration suite |
| SOGo | Collaborative software server focusing on simplicity and scalability |
| Kolab | Secure, scalable, and reliable groupware server |
| eGroupware | Enterprise ready web-based groupware suite |
| OpenMeetings | Video conferencing, instant messaging, whiteboard, and other groupware |
| Citadel | Complete and feature-rich groupware server |
| Kopano | Groupware application suite originally based on Zarafa |
| grommunio | Modern, digital communication and collaboration |
| HordeGroupware | Popular full-featured groupware server |
Read our verdict in the software roundup.
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