The Citadel Groupware Server

The time has come to consider moving that expensive, high-maintenance Windows system to a sleeker, more robust Linux system. The gap analyses have been done, the meetings held, the presentations complete, and now it's go time. Although installing and configuring a Linux server back end can be challenging, we all know that users aren't going to care about that. What they want is uninterrupted functionality so they can continue doing their jobs. Although migrating users from applications such as Microsoft Office to OpenOffice.org is generally an intuitive task, the 800-pound gorilla that's keeping you up at night is e-mail and groupware. How are you going to provide and manage Microsoft Outlook-like functionality to the masses? In a word, Citadel.

One of the understated wonders of the Free and Open Source Software world is the Citadel Groupware Server (www.citadel.org). Controlled by a single developer, Citadel started life in 1987 as a UNIX version of the already-existing Citadel-CP/M application. Almost 20 years later, the modern-day Citadel boasts all of the functionality of a mature groupware server. One of the miracles that Citadel can perform is providing all of the most-used functionality of Microsoft Exchange with little fuss and and even less cost.

Many modern organizations are coming to the realization that their IT budget is largely controlled by Microsoft's licensing fees and hardware requirements. Although organizations can prepare for some of these costs, many are looking at Vista with trepidation. Although the hardware requirements for Vista aren't obscenely over the top, many organizations still will need to upgrade their hardware in order to run it. And, sooner or later, run it they will. The hardware upgrade cycle is a never-ending source of pain for some organizations, because not only do servers and server software need to be upgraded on a somewhat regular basis, but untold numbers of workstations also need attention.

Depending on the size of your organization, your Microsoft Exchange server might be the most robust server in the closet, and finding a suitable replacement for Exchange is quite often a show-stopper. Citadel is a groupware solution that allows organizations not only to avoid upgrading software, but it also runs on a significantly lower-powered machine, thus breaking the hardware upgrade cycle for years to come.

It's always good practice to install and test everything on a test server before moving it into a production environment. Swapping out your mail server is certainly no different, and you should keep your Citadel testing as far away from your production system as possible. Obtaining and configuring Citadel is several orders of magnitude easier with an Internet-connected server, however, because you can avail yourself of the Easy Installation process.

As of this writing, the most current version of Citadel is 6.84. I highly recommend a trip by the Citadel site in order to obtain the most current version of the server and the most current version of the installation instructions. Our testing environment consisted of Debian Sarge with a 2.6 kernel running in VMware Player 1.0.2. For no particular reason, we selected the Web server installation option, but virtually any installation category should work, as Citadel installs everything it needs. In the past, we have installed and run Citadel on a Debian Sarge server proper, and in both cases the installation was flawless.

I cover the Easy Installation method here not only because it's easy, but it's also fairly undemanding on resources and therefore quite likely that anyone can make use of it. Just about the only requirement for the Easy Installation method is a working—and preferably fast—Internet connection.

The Easy Installation method requires the toolchain, or build environment, to be present on the target platform. In addition, curl (or wget) is required. If you'd like to support SSL connections to the server, you also need libssl-dev. On a Debian system, use the following command to install or verify your build environment:

apt-get install build-essential curl libssl-dev

Before installing, it is worth noting that Citadel is designed as a black box system running on your server. Part of that black box means that Citadel authenticates logins against its own user database and not against your system user database (typically /etc/passwd). If you'd like Citadel to authenticate against your system user database, you must export the IS_AUTOLOGIN variable to the environment prior to running the Citadel install, like so:

export IS_AUTOLOGIN=yes

Now that the environment is set, it's time to kick off the Easy Install with the command:

curl http://easyinstall.citadel.org/install | sh