Zentyal
Open Source
Zentyal is an open source email and groupware solution based on Ubuntu Linux.
SOGo
Open Source
SOGo (Scalable OpenGroupware.org) is an open source collaborative software (groupware) server with a focus on simplicity and scalability.
Kopano
Open Source
Kopano is an open-source groupware application suite originally based on Zarafa.
iRedMail
Open Source
iRedMail is a free, OpenSource mail server.
mailcow
Open Source
mailcow is a mail server suite.
Kolab Community
Open Source
Kolab is a free and open source groupware suite.
Zimbra Collaboration Suite
Freemium
Zimbra offers an open source email platform for the enterprise.
Zarafa
Commercial
Zarafa is an open-source groupware application.
OX Open-Xchange
Open Source
OX Open-Xchange is a web-based communication, collaboration and office productivity software.
Compare Microsoft Exchange Server with alternatives
Compare Zentyal and Microsoft Exchange Server and decide which is most suitable for you.
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