An Open Look at Groupware

Open source groupware is better than ever, but for those seeking to replace Exchange, some caveats apply. Jim Conley examines the state of open source groupware and why it matters in a Microsoft shop.

Microsoft pulls the plug on Exchange 5.5 Server on Dec. 31 after eight years of steady service. While most of the Exchange 5.5 population has migrated to Exchange 2000 Server or Exchange Server 2003, some analysts estimate that as many as 25 million seats will still be on Exchange 5.5 at the beginning of next year. Without support from the mother ship, admins are on the lookout for their next platform--which may not be Microsoft. And as Microsoft is finding with Linux, open source alternatives are enticing many of those looking to switch.

Open Source vs. Runs-On-Linux
A quick refresher for the Windows crowd--open source and "runs-on-Linux" aren't synonymous, especially when talking about Exchange alternatives. Bynari Insight Server is an excellent Linux-based Exchange replacement, but isn't open source. Projects such as and Open-Xchange are open source. In theory, an administrator could build an open source groupware solution with no costs beyond hardware and developer time. In practice, most groupware servers running on Linux (including those based on open source) use some closed-source components, especially if Outlook is the intended client.

A variety of open source servers replicate the basic functionality of Exchange 5.5, but accessing data from a Windows desktop requires either a proprietary connector for Outlook or a user base willing to try a Web interface to access much of anything beyond e-mail. Outlook connectors may carry substantial licensing fees, but they do offer the most painless transition on the client side. Users know Outlook, and many power users rely on Outlook. While Novell has announced a future port to Windows of its popular open source groupware client Evolution, for now Outlook is the messaging client of choice for corporate Windows environments.

Messaging vs. Groupware
For the majority of users, Outlook remains a personal information manager rather than a groupware client. Recent statistics from Radicati Group analysts on the number of corporate clients using Outlook (489 million) versus the number of Exchange seats (127 million) suggest how few organizations actually take advantage of the groupware functionality of Outlook and Exchange. Public folders, calendar sharing and resource scheduling all require Outlook to be operating in Workgroup mode, which means an Exchange server on the back end.

Of those 127 million Exchange seats, the actual groupware usage varies dramatically among organizations. Some firms take advantage of little more than Exchange's Global Address Book, while others rely on complex solutions based on custom Outlook forms and server-side events. Those with extensive groupware customizations will find the transition to open source more difficult and, in some cases, impossible without a complete redesign of the application.

The Cost of Connecting Outlook

Outlook connectors don't come cheap. The SKYRiX ZideLook connector costs $65 per user, according to SKYRiX's Web site. Netline's OXLook, when bundled with SuSE Linux Openexchange, costs $1,319 for 10 seats. Bynari's Insight Connector is significantly cheaper than ZideLook and OXLook—$439 for 10 users, including the server.

— J.C.

Even for domains that use Exchange primarily as a messaging server rather than as a groupware platform, implementing an open source solution requires careful planning for a successful migration. Companies such as Binary Tree offer products and services for moving an Exchange store to an open source server. Evaluating one of these solutions is a good idea when considering a migration. vs. Open-Xchange
The distinction between groupware and messaging mirrors the difference between the two most mature open source groupware solutions suitable for replacing an Exchange environment, and Open-Xchange. The products share similar lineages. Both originated in Germany as closed-source groupware solutions running on Linux. Both developers (SKYRiX for and Netline for Open-Xchange) subsequently donated the code base to the open source community while retaining proprietary Outlook connectors as a revenue source. focuses purely on groupware solutions, leaving messaging to other parties. Open-Xchange incorporates both messaging and groupware into a single package. and Open-Xchange are by no means the only open source groupware solutions, but they're the most viable Exchange replacements because of the availability of corporate support and active development communities. Open-Xchange remains the most popular corporate groupware package, largely because of its historical association with SuSE Linux, which was acquired by Novell in January 2004. SuSE, Europe's most popular Linux distribution, has offered Open-Xchange under the name Openexchange as an Exchange alternative since 2001 under license from Netline. Since Novell acquired SuSE, Netline open-sourced the majority of the Open-Xchange server code in August 2004 and now offers both free and licensed versions. The critical distinction between the versions is the inclusion of a proprietary Outlook connector (Netline's OXLook connector), installation tools and product support. may lack integrated messaging services but it does include SKYRiX's SOPE application server, which includes 16 packages and 1,500 classes handling XML, MIME, IMAP4, LDAP, RDBMS and iCalendar. Many of the underlying components of are identical to those in Open-Xchange. Still, administrators considering the development of custom groupware applications need to carefully examine the relative advantages of each product as a platform. project leader Gary Frederick described the project as "an Exchange take-out" when the SKYRiX code was open-sourced in July 2003. But by itself is not an Exchange replacement due to the lack of a messaging server. can be installed as a groupware component over an Open-Xchange server or it can interoperate with pre-existing messaging servers.

Developing Open Source Groupware
Both and Open-Xchange provide extensive libraries for the development of groupware applications. Developers considering adapting groupware based on Outlook and Exchange must keep in mind that with open source groupware, much of the code will be on the server instead of the client. An Outlook/Exchange groupware solution usually consists of customized Outlook forms with VBScript event code, VBA modules for application-level events and C++ add-ins for radical customization and low-level messaging programming. An open source groupware solution that demands programmatic business logic will generally require a Web interface because of the lack of a client-side application library comparable to Outlook's Messaging API.

Although the code for Open-Xchange and is publicly available, learning how to customize or manipulate the software is an uphill climb, especially for those used to MSDN documentation. The core of knowledgeable open source groupware developers is significantly smaller than for Exchange, and the solution for many issues is determined through trial and error. That being said, the underlying components of open source groupware are established open source services such as Postfix (a mail transport agent for handling routing and delivery of e-mail), Cyrus IMAPD (an IMAP4 mailbox store), OpenLDAP (LDAP authentication), PostGreSQL (database) and Apache (Web). Organizations already using Apache and Postfix for Web and messaging services have an advantage when considering open source groupware packages because existing infrastructure can be used as the base for a groupware installation.

The Next Generation
While and Open-Xchange are the most mature open source groupware solutions, projects such as the Kolab Server and the Chandler and Sunbird personal information manager applications could have a significant role in the future of open source groupware. The Kolab server is associated with the KDE desktop on Linux, an alternative to the Gnome desktop that the Novell Evolution client is based on. Although Kolab will interoperate with a variety of clients, Kontact, the personal information manager for KDE, is the target client application. The roadmap for Kolab suggests a groupware solution designed for advanced client-server integration comparable to Outlook and Exchange.

Why Outlook Is So Hard To Connect To

Outlook communicates with Exchange through TNEF (transport neutral encapsulation format), a method to pass text, files and objects as well as binary message data that contains Microsoft Messaging API (MAPI) properties. Any genuine MAPI provider for Outlook needs to be able to create and interpret TNEF data. This is not a trivial task, especially considering the high number of undocumented features in the MAPI object model (160 and counting).

— J.C.

The Chandler project by the Open Source Applications Foundation, while very much in alpha, is a cross-platform (Mac OS X, Windows, Linux) open source personal information manager that could be a future Outlook competitor. If Chandler matures into a full-featured groupware client while remaining platform agnostic, it could be a viable Outlook replacement on the Windows desktop with a seamless migration path to an open source desktop. Mozilla's Sunbird project is equally exciting, if only slightly more mature than Chandler. Sunbird is a calendar extension for Thunderbird, the mail client that uses the Firefox browser. What makes Sunbird interesting is that it's based on Mozilla's XUL language, which allows for the development of stand-alone applications far more functional than traditional browser-based interfaces. As with Chandler, the option of running Sunbird on a variety of platforms also provides greater flexibility for administrators.

Active Directory Considerations
Perhaps more than any other Microsoft product, post-5.5 versions of Exchange rely on AD integration. Replicating some features of Exchange without AD is nearly impossible. Take the Global Address List and Public Folder permissions, for example; no existing open source solution comprehensively replicates these functions. Managing open source groupware permissions is a completely separate process from managing domain permissions. For an organization with 25 people, independently re-establishing directory permissions is a manageable annoyance. For an enterprise with thousands of users, it presents a logistical nightmare. But for those still on Exchange 5.5, the lack of AD integration isn't a concern, and may even be a benefit of an open source groupware solution.

Worth a Look
With a planned Windows port of Novell's Evolution and the rapid development of Sunbird and Chandler, the availability of an open source client capable of providing functionality comparable to Outlook seems imminent. The Outlook connector serves best as a temporary measure for open source groupware, a way of leveraging existing Windows desktops with a mature closed-source client as an entry point for open source. For Exchange administrators considering any messaging or groupware upgrade or migration, open source groupware deserves a look. With Windows-based open source client alternatives to Outlook not yet fully baked, open source groupware will remain an unfeasible work in progress for some; others will find the possibilities of server-side groupware carry enough immediate benefit to replace an Exchange installation.


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