Scalix collaboration platform, with its latest release version 11.4, aims to be a good alternative to Microsoft Exchange. Based on the HP OpenMail platform, discontinued by Hewlett-Packard in 2001, it has been further developed by Scalix and now acts as an enterprise email and group calendar server with the option of integrating systems like ERP, CRM, and billing into the Scalix system using its open API. It is compatible with most LDAP authentication mechanisms, such as those in Windows Active Directory, Novell eDirectory, and Red Hat Directory Server. The most prominent feature of Scalix is its Exchange compatibility; you can use an Outlook client to access the Scalix platform. Scalix also provides an AJAX-based client that is nearly identical to Microsoft Exchange Outlook Web Access (OWA). Aside from Outlook compatibility, Scalix also claims to coexist peacefully with other existing Exchange email systems.
Version 11.4 of Scalix, released in May, offers several new features and upgrades. Web-based access has been improved by adding theme customization and an overlay calendar, which allows you to view multiple calendars at the same time in day, week, and month views. Firefox 3 is officially supported. The new release supports data feeds (RSS and ATOM) using Scalix proxy folders. Optional antispam and zero-hour antivirus, based on Commtouch technology, have been added. CentOS 4 and 5, which were not supported as platforms for previous versions, now are.
Scalix offers four packages: the Community Edition, Small Business Edition, Enterprise Edition, and Hosting Edition. The four vary by the number of standard and premium users, support levels, and additional advanced features. The difference between standard and premium users is that premium users can have access to advanced features of Scalix, such as establishing an Outlook connection with Scalix, while standard users are limited to basic features such as POP/SMTP/IMAP, calendar, and Web-based email -- so for Scalix to be a true Exchange alternative, most of your users must be premium users. While it is true that mail servers such as Postfix and Sendmail can't provide all those features, other open source mail servers, such as Courier Mail Server, can in a webmail environment. Another popular mail collaboration suite, Zimbra, can provide the same functionalities, but an Outlook connector is not available on its open source edition.
For the free Scalix Community Edition, you can have unlimited standard users and up to 10 premium users. The Community Edition doesn't support advanced features and add-ins like high availability, antispam, antivirus, and Exchange coexistence. The Hosting Edition offers all the features, including multi-server support, but requires 100 premium users as its minimum when you purchase it. Choosing the appropriate edition boils down to the number of premium users you want. For complete details of Scalix editions, check the company's comparison chart.
With an abundance of high quality documentation and resources, installation of Scalix is easy and straightforward if you meet all of the software's requirements and have the necessary dependencies. Before installation, be sure that your Linux distribution is supported. Version 11.4 runs under Red Hat Enterprise Linux (RHEL) 4 and 5, CentOS 4 and 5, and SUSE Linux Enterprise Server (SLES) 4 and 5. Fedora 7 and openSUSE 10.2 are also supported, but running Scalix on either is not recommended for a production environment because these two distros are community versions of Red Hat Enterprise Linux and SUSE Linux Enterprise Server respectively, and important patches and updates available for the enterprise versions may not always be available for the community versions. Finally, 1GB of memory is recommended and 1GB of disk space is required for the base installation, plus additional space for user mailboxes.
For this article, I installed both the Community Edition and Enterprise Trial Edition on a RHEL 5 server. During the installation process, I encountered problems with both the network environment and the dependencies, but installation continued smoothly once I resolved everything.
I was surprised to find that the Scalix installation will stop if SELinux is enabled on the system, and it will recommend you disable or put SELinux into permissive mode for the installation to continue. While the Scalix installation instructions do say that it is better for the firewall to be disabled, for a self-respecting network administrator, that is unacceptable. Since mail servers are exposed to outside threats, disabling the firewall is not a good idea. However, I was able to proceed without any difficulties by merely disabling SELinux with the firewall enabled.
Scalix requires that Apache, PostgreSQL, and Sendmail already be installed and will install Tomcat during the installation process if it needs to. The Tomcat installed by Scalix is its own special version (though the company doesn't say how it differs from the standard version), meaning that you have to depend on Scalix for future Tomcat updates. As for Sendmail, I think Postfix is a better choice in terms of security and, since Scalix also claims to work with Postfix, there should be an option to select Postfix during the installation.
Scalix configuration and management
After the installation is complete, the Scalix services work right away. Using a username and password generated during the installation, I quickly established a Web mail session. The Web mail client is based on AJAX and the interface is similar to that of Exchange OWA, so anyone who uses OWA will feel comfortable. Scalix Web mail and calendar features are comparable to those of OWA, but OWA offers more flexible features such as sending email at a specified time and appointment scheduling, which Scalix Web mail lacks. I tested Web mail using IE7 and Firefox 3 and encountered no problems. Still, because of the Web client's limited functionality, premium users will likely stick to using Outlook. One security concern that I have with the Web mail is that it doesn't redirect to an SSL session when a user logs in.
I also tried using Outlook 2003 to connect to Scalix. For Outlook to connect to Scalix, you must first install a connector on the client. For large networks with many clients, there is a guide available detailing automated deployment of the Outlook connectors using group policy and other methods so that client deployment is less of a problem. After that, just create a Scalix profile in Outlook and you can retrieve messages and configure your calendar to synchronize with Scalix.
With the Scalix administration console, you can easily manage settings with one simple interface. Unlike the Web mail, the administration console automatically uses SSL when you connect. You can manage server settings, view queue contents, create users and mailboxes, enable and disable services, and even monitor Scalix server status by services and logs. Everything you have in Scalix you can find in Exchange, though the Scalix administration console is a little more simplified than that of Exchange.
With regards to LDAP integration, Scalix works surprisingly well with Active Directory. With Scalix Active Directory extensions, which are available for the Small Business Edition and above, you can easily synchronize Active Directory users with Scalix. You can also create Scalix users, their account settings, and mailboxes, and configure mail nodes, using Active Directory.
Overall, Scalix works well as a mail and groupware server, comparable to Exchange, but I found a few concerns that need to be addressed, such as the fact that backup and restore operations need to be done from the Linux command line instead of being integrated with the administration console. Also, since Scalix targets existing Exchange users, administrators who are used to Exchange must learn Linux as well as technologies like Tomcat and PostgreSQL.
Can we finally replace Exchange?
One selling point of Scalix is that its features are comparable to those of Exchange for a lower cost. However, if you look at Scalix pricing, you will see that, when comparing the Scalix Enterprise Edition, Scalix would incur a higher cost than Exchange over the long term. While Scalix costs less during the early years of deployment, an increasing number of premium users ($60 one-time, perpetual license fee for each premium user for the Scalix Xandros Edition), yearly OS subscription cost (Red Hat, for instance, runs $1,000), yearly patch and update subscription ($12 per client), and support costs ($300 per email incident) can easily make Scalix cost more than Microsoft Exchange in years to come.
Unless Scalix changes its pricing plan, I recommend reserving Scalix for small businesses with few users who wanted to try email and groupware solutions for Exchange capabilities. Those who already have systems based on open source distributions supported by Scalix can also benefit since no migration is necessary and the cost of OS subscription will be factored out of the equation. Anyone having an existing Exchange infrastructure probably should stick with what they have unless there are some changes with pricing and additions of notable features. However, it doesn't hurt to try the Community Edition or Enterprise Trial Edition of Scalix for free.