Stories by Steve Hultquist

Sophos NAC is a good start

The wide variety of so-called NAC (network access control) products on the market shows a broad range of thinking about policy-based security controls and the management of the network in general, including the end-point devices that connect to the network. Some vendors enforce policies using a client agent, some enforce them in the network, and some even use peers for enforcement. Network-based enforcement itself can take many forms, including dedicated gateway, DHCP manipulation, 802.1x authentication, and port- and VLAN-based enforcement on switches.