Good Open Source Alternative to Microsoft Exchange?
 

In my environment I have several workstations running Microsoft Outlook (not express) on Windows 2000/XP/Vista.

Is there a way those clients can work with a Microsoft Exchange equivalent on a Linux server (say Fedora Core)?

My initial search discovered OpenChange - but I have no idea how mature or stable it is. It is currently version 0.4 only.

Also, since I am not an expert in Microsoft Exchange, it is hard for me to judge which "groupware" is a good candidate for this function. I even found this nice list: http://linux.softpedia.com/get/Office/Groupware but I have no idea which one is "Outlook-compatible" and which isn't.

I would appreciate any tip or pointer that can help me focus on studying a suitable solution or two.

Thanks,
Alex

If you are not using the shared calendaring functionality, Outlook can work with any smtp/pop3 server (like sendmail/dovecot). Only a very small percentage of Outlook users actually use the product fully from my enterprise experience. As a result, using an exchange server is overkill.

Perhaps you should start by determining the functionality you need in the backend.

I've never used it, but Zimbra has been getting a lot of attention as a good groupware solution.

Thank you for your reply. I am actually looking for a solution that would allow me to share not only calendars, but also a few email accounts. This is of course not possible with a shared .pst file and only an exchange based solution (or similar) allows it.

Any other ideas (in addition to Zimbra - thank you Hangdog42)?

In the meanwhile I managed to hear about Kolab but I don't know much about it and I don't know whether it is transparent as an exchange replacement or I need to do some customization on the client side.

In fact, any general introduction to the protocols involved in this setup would be very helpful to me eventually figuring out the optimal solution for me.

Thanks,
Alex

You can also take a look at Open-Xchange Server.

OpenGroupware
 

I, and my employer & clients, have been using OpenGroupware since 2003. OpenGroupware is a very feature complete (competes with M$-Exchange & Lotus Notes) enterprise groupware server scheduling, tasks (with workflow/delegation), and contact management. Rather than just another WebUI OpenGroupware provides a true groupware platform with WebDAV, GroupDAV, and an XML-RPC API.

http://www.opengroupware.org - the server's feature list is available at - http://www.opengroupware.org/en/applications/index.html

I've been using this so long I've begun writing an Administrator's guide:
http://docs.opengroupware.org/Member...ogag/file_view

We searched for a long time before choosing OpenGroupware, and were nearly ready to buy Lotus Notes; OpenGroupware is the only truly Open Source *enterprise* groupware server.

There is also a commercial [but inexpensive] M$-Outlook plugin that provides a real MAPI provider (vs. some weird PST sync thing) to provide complete Outlook functionality including off-line mode.

Thank you for your well thought reply.

Unfortunately, as macemoneta warned, this OpenGroupware might be an overkill for my little network. Here is an attempt to refine my requirements:

I am actually looking for a solution that would allow me to share a calendar (or two) and 1-5 mailboxes (or .PST files) among 2-4 users.

Is this possible? on a Linux server, that is?

Thanks,
Alex

Zimbra is a very nice exchange replacement solutions. keep in mind if you need certain functions they are not available in the Free versions, only in the commercial version. Once you see the web interface though I doubt you will NEED the outlook client support, and you probably don't need the Treo, or blackberry support..

You can fire up an Ubuntu box (or RHEL / Centos, or Suse) and download the packages for Zimbra and have it up and running in about a half hour on your first attempt. they really did a nice job packaging this solution.

You can easily accomplish the shared calendaring with any email client that supports iCalendar (ICS) or CalDAV (like the free Thunderbird email with the Lightning calendar plugin, Outlook on Windows, iCal on the Mac, etc.). On the server side, this can be as simple as setting up apache with webdav.

For the email portion, a typical sendmail/dovecot configuration will easily do the job.

This is functionality available with any mainstream Linux distribution. The best part is that it's all standards based, so you can mix and match products across platforms (no lock-in). You could even replace your own server with Google Gmail and Google Calendar if you don't want in-house servers - and it will work exactly the same on the client side.

OK - this is the second recommendation for Zimbra, and since my server is actually running Fedora Core 4, I started downloading the package for it.

However, as soon I started downloading it, I noticed its size: 198.7 MB. This is huge! Certainly not what I was thinking about. This must contain GUI of some sort, right? Perhaps even written in some scripting language (vs. C/C++)?

I was thinking more of a thin layer managing simultaneous access to .PST files (or similar) - similar to what macemoneta described in regard to webdav/dovecot. Something that works with Outlook, not a standlone Web application.

Thanks,
Alex

The package is large because they give you everything, postfix, imap server, anomy sanitizer, spamassassin, web server for the webmail, clamav, etc, etc all tested and working.

Most other packages give you there customizations but you are still responsible for setting up the rest of the environment correctly or it doesn't work. Zimbra has simplified it by putting all the requirements together in an easily installed package, which is why it is so easy to get working. and no it's not just a web mail server, it will do calendaring scheduling, av spam filtering, message archiving, search and retrieval, even with outlook if you prefer.. Kinda silly to write something off without even looking at it because of the size of the download.

Open Groupware has a Live CD so you can try it out... not a small download either. It is a great solution as well.

Zimbra you can test most of it on their website, but if you really want to play install it on a spare machine.

Both are good solutions, I just found zimbra to be put together incredibly well, quickly installed, documented, supported, I was extremely impressed in a very short amount of time.

Good Open Source Alternative to Microsoft Exchange?
 

>Unfortunately, as macemoneta warned, this OpenGroupware might be an >overkill for my little network. Here is an attempt to refine my >requirements:
>I am actually looking for a solution that would allow me to share a >calendar (or two) and 1-5 mailboxes (or .PST files) among 2-4 users.
>Is this possible? on a Linux server, that is?

Sure, OpenGroupware. :) If you want Outlook support you *MUST* have a server and a MAPI provider, that is the fundamental nature of Outlook.

There are some PST file sync utilities floating about but these all try to work around the fundamentals of Outlook psychology; and thus will give you fits. Of course, you can always install Exchange... :)

You need a fat solution in order to keep Outlook, or ditch outlook and there are allot more options.

Hmmm... I did download it, looked at the installation instructions and... was shocked: minimum requirements for production environment is:

My Fedora Core 4 server is running on a mini-itx box using 1GHz CPU and 512MB. Since it is running 24/7, I wanted my server to use as little power as possible (without affecting functionality). So far, this server was more than adequate for my needs. I do not wish to update the hardware just because of Exchange functionality.

The more I look at it, the more I become convinced that macemoneta's direction is the correct one. This server is already running Apache, MySQL, Samba, CUPs and other daemons and background processes. Zimbra seems like an overkill (for 2-4 users).

Thanks,
Alex

You asked for something that compared to Microsoft Exchange... If you were using MS Exchange what sort of system requirements do you think it requires ?

If you only have 2-4 users, I'm sure the Testing environment requirements would be overkill for Zimbra.

But hey whatever.. in your RFC you never specified what equipment you planned your installation on, only the commercial product you wanted the equivalents to. a system that meets those min requirements is around $600.00 these days, so I still don't see what the big deal is.

So what's the deal on this iCalendar (ICS) or CalDAV... My brother is an MS guy and he's been interested in ditching exchange but needs to keep Outlook and it's shared calendar.... probably 25 users no more than 50 for sure. How would this work... Outlook calendar works off this package but still connects to something like Citadel or whatever for email?