Our editors pick the products and services we write about. When you buy through our links, ZDNet may earn a commission.


  • Editors' rating
    6.5 Good


  • Native MAPI support
  • Works with most Linux distros
  • Nice AJAX-based web client


  • Command-line management tools
  • Plug-in still required for Outlook support
  • Integration with other open-source applications is required for complete solution

Zarafa differs from other Microsoft Exchange alternatives because it's an open-source product. That doesn't exactly make it unique, as there are a number of rival open-source Exchange alternatives available — not least the aptly named Open-Xchange, plus Scalix and Zimbra, which is now a part of Yahoo! All are worth investigating, but Zarafa stands out from the crowd as it's an almost seamless replacement for Microsoft's product.

The key to understanding what Zarafa is all about is the way it connects users with their inboxes and other data — specifically those using Outlook. By default, Exchange Server uses Microsoft's MAPI (Messaging API) to talk to Outlook and because that's proprietary the competition tend to use Outlook plug-ins to translate MAPI to the more open IMAP/SMTP protocols used by their servers. Zarafa, however, implements its own MAPI provider (Mapi4Linux) at the server end, effectively making the Zarafa host look just like an Exchange server as far as Outlook is concerned.

As with most open-source applications, Zarafa software can run on most of the leading Linux distros. Red Hat and SUSE Linux Enterprise are the preferred platforms for large deployments, but Debian, Ubuntu and others can all be employed. The source is also available for compilation on other platforms, and there's a ready-to-run VMware appliance complete with custom Ubuntu server OS.

We tried both a standard Linux download and the VMware appliance. In both cases, installation was quick and easy, with little to do other than specify the domain we wanted to support and configure a few users. Unfortunately this all has to be done from the command line. The same goes for other management tasks, as there's no fancy graphical management interface like those found on more conventional Exchange alternatives.

On the plus side, Active Directory and LDAP integration is available to help automate user setup and there's support for 'brick-level' backup and recovery. You can also configure antivirus and anti-spam protection, although this has to be done via integration with other open-source applications such as ClamAV and SpamAssassin, as there are no bundled security tools to speak of. This is all part of the open-source ethos, which is fine, but a fair amount of technical expertise will be needed to get Zarafa configured the way you want it.

User setup is more straightforward. Despite the native MAPI support, a plug-in is still needed to enable Outlook to communicate with the Zarafa server, but deployment can be automated and the plug-in works with any version from Outlook 2000 onwards.

Top ZDNET Reviews

Once configured, the Zarafa plug-in delivers a familiar Exchange-like experience with the expected single folder hierarchy and immediate notification of new messages. There's support for a global address book, folder sharing and group calendars, with all the usual scheduling options including the ability to find free/busy time and manage meeting invitations. The client also provides offline access and synchronisation using Exchange Server ICS (Incremental Change Synchronization) technology.

Much the same groupware features are also available to users of the AJAX-based web client, called WebAccess. Zarafa uses the open-source Apache web server to deliver this option. Like Microsoft's OWA, this tries to mimic the Outlook GUI and, despite looking a little dated, is both responsive and easy to navigate with drag-and-drop capabilities to copy and move items between folders, for example.

There's support also for POP3/IMAP access using other clients and iCal compatibility plus something called Z-Push, an open source implementation of ActiveSync, for wireless mobile users. BES (Blackberry Enterprise Server) integration is yet another option, again, making the Zarafa server more or less plug compatible with its Exchange role model.

Zarafa claims to be able to halve costs compared to Exchange — but just because it's open source don't assume you can get the software for nothing. A community implementation can be downloaded free of charge, but this is limited to supporting just three Outlook clients. For large-scale deployment, and in order to get proper support and training, a commercial licence is required with a choice of Standard, Professional and Enterprise editions to suit.