The Antigen product from Sybari Software (now a Microsoft subsidiary) offers AV protection and content-filtering for IM systems using either Microsoft's Live Communication Server 2005 (LCS 2005) or IMLogic's IM Manager products. It integrates into these systems and extends their capabilities.

By focussing on the content control aspects of IM, Antigen can provide efficient and effective security measures that are independent from other controls applied to other systems.

The client stations need to be running Microsoft Windows 2000 Professional or XP Professional. We used LCS on Windows Server 2003, and although the system allows for public internet access as well as intranet links, we chose to restrict it to internal messaging only. This allowed us to test the antivirus features with real viruses without inadvertently spreading them to the outside world.

However, because Antigen is integrated with the server software, Sybari's security features could be applied to traffic sent via public servers as well. This could be useful where organizations wish to allow staff to have access to these services while retaining some control over the message content.

We also used the latest version (5.1) of Microsoft's Windows Messenger client to remain compatible with LCS 2005. The Antigen Central Manager's management facilities allow you to create and schedule batch jobs, from obtaining current version numbers of antivirus versions to scheduling automatic updates of virus signatures and scanning engines. This capability will be appreciated by system admins who will be able to arrange for the system to take care of complex routine operations without requiring further attention.

The product uses several antivirus scanning engines for in-depth inspection of the contents of both messages and attachments. Its document filtering facilities can examine message text using a selection of keyword lists that can be selectively applied according to user requirements. The system provides detailed auditing data, and can send operator alerts to specified email accounts when specific conditions, such as virus detection, occur.