Zimbra is not an open source Exchange substitute

by Dustin Puryear

I just saw a note that yet another VAR is offering Open-Xchange to its client. Not a big story, but it did get me thinking about the current marketplace for open source Exchange replacements.

Let’s keep in mind that the “open source” market for Exchange replacements is actually a tad on the muddy side. Most of the replacements are more about being free, to some extent, than completely open source, e.g., Zimbra is MOSTLY open source, but the commercially licensed software does come with software that is not exactly open. Ditto for Scalix and a few others.

So maybe we should just consider Exchange replacements. Off the top of my head, we have:


OSER you say? Well, that’s new to me too! I just found it via a Google search. OSER is the “Open Source Exchange Replacement Platform” (I don’t think “Platform” made it into the acronym).

Hmm, getting back to “open source”, how should we define “open source Exchange replacement”? Here are my thoughts:

First, if it’s an “Exchange replacement”, it must support Outlook and Outlook functionality. Otherwise, it’s not an “Exchange replacement”. It may be a groupware solution, but it’s not replacing Exchange. So, to me, this takes out mixed licensed applications such as Zimbra. Zimbra is an open source groupware application, but not an open source Exchange replacement. You don’t get the source code to what makes Zimbra an “Exchange replacement”. This goes for anyone that doesn’t offer the source code to their Outlook connector IMHO.

Second, well, that’s it really.

We have a good market for open source groupware, but not so much for open source Exchange replacements.

I think the point to take home here is that there really aren’t many players that are truly offering an open source Exchange replacement, but there are many players that offer an open source groupware framework and that offer closed source Exchange functionality that makes them a true “Exchange replacement”.

P.S. Yes, I like Zimbra.


Gray Rothkopf
2008-08-02 12:23:13
Zimbra may not meet your criteria for an open source Exchange replacement, but it does meet the needs for many organizations looking for an alternative to Exchange, from a company with a commitment to cross-platform support, varied mobile device over-the-air sync compatibility, and a straight-forward wizard to migrate from Exchange.

Glad you like it, visit our blog on Zimbra some time.