Sophos is joining Cisco's Network Admission Control (NAC) program.

It will integrate the Cisco Trust Agent (CTA) into Sophos Anti-Virus. Sophos is the latest anti-virus software vendor to participate in the NAC programme, joining Computer Associates, McAfee and Trend Micro.

Announced in November 2003, the Cisco NAC programme is part of Cisco's Self-Defending Network strategy. It allows Cisco routers to evaluate client security information, such as whether a particular computer's anti-virus definitions are up to date, before allowing it to connect to a network. Machines that don't adhere to network security policies can be denied access, quarantined or allowed only limited access to network computing resources.

In joining the NAC, companies such as Sophos modify their products to communicate with the CTA, which is installed on laptops, home desktops or servers, or mobile devices that will be connecting to a computing network. The CTA collects information from other security software clients including anti-virus clients, and relays that information to Cisco devices on the network.

In October, CA said it would integrate the eTrust PestPatrol Anti-Spyware and eTrust Antivirus products with the Cisco Trust Agent.