Is there any open source Exchange server that is work fine like Microsoft Exchange for Linux or Windows?

closed as off topic by mgorven, Scott Pack, Wesley, sysadmin1138 Jul 2 '12 at 22:06

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  • As time moved on, questions like this are no-longer considered topical. Specifically, product recommendation questions, including OSS alternatives recon, is considered off-topic per the FAQ. – sysadmin1138 Jul 2 '12 at 22:07

Zimbra is an open source alternative to Microsoft Exchange. It uses a number of open source products, namely Postfix, Tomcat and OpenLdap. It can interact with Active Directory and other directory structures. It also offers a pretty extensive AJAX enabled web interface.

It offers most of the features offered by Exchange:

  • Email
  • Contacts
  • Shared Calendaring
  • VOIP integration
  • Mobile access with activesync push sync and Blackberry Enterprise Server connector
  • MAPI, IMAP, POP, iCal iSync Access
  • Extensive web interface

It offers both an open source and commercial version, and is now owned by Yahoo.

  • Do you still recommend this, 3 years later? Thx – Neil McGuigan Dec 13 '12 at 6:10

Ahh...the white whale of open source, the Exchange killer. There's no shortage of competitors:

And, for those that aren't necessarily looking for free (in either sense), but just don't like Microsoft or Exchange:

  • PostPath is (as far as I know) the closest you'll get to a "drop-in" replacement for Exchange; but it sounds like Cisco has spirited it away to the dungeons beneath their offices. Scalix is based on HP OpenMail (en.wikipedia.org/wiki/HP_OpenMail). – Avery Payne May 14 '09 at 22:34
  • Heck, GroupWise even has BlackBerry support. Though you'll need a Windows server to run the BES. – sysadmin1138 Jun 8 '09 at 16:48

There is an Exchange-like open source project called Open-Xchange.

It is a messaging and collaboration platform combining common free software packages, open standards and web services. Open-Xchange Server is available as proprietary software and as a community supported open-source software (GPL 2) package.


See this article about Zafara groupware.


We evaluated http://www.kerio.com/ when we moved away from Exchange 5.5, and it seemed quite polished.

  • +1 for Kerio. We use it with Entourage client or Mail.app on our macs, and even have over-the-air email/cal/address push to our Nokia and iPhone mobiles. Works great, and integrates with our OpenDirectory for users, groups, and authentication. – lukecyca Jul 7 '09 at 23:12

It is not open source, but the community edition of Scalix is free-as-in-beer. Never used it myself but I've heard really good things about it.


I've not tried it personally but take a look at http://www.zimbra.com/

It's dual licensed but the opensource one might give you everything you need.

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