in IAS since NT4), support for IEEE 802.1X port-based authentication, and other features. All versions of IAS support multi domain setups. Only Windows Server 2003 supports cross forest. While NT4 version includes a Radius Proxy, Windows 2000 didn't have such a feature. Windows Server 2003 reintroduced the feature and is capable of intelligently proxy, load balance, and tolerate faults from faulty or unreachable back-end servers. References External links Deploying Internet Authentication Service (IAS) in Windows 2003 Internet Authentication Service in the Microsoft Windows 2000 Resource Kit Article describing how to log IAS (RADIUS) + DHCP to SQL IAS Log parsing utility. Allows to visualize ias log files Microsoft Windows security technology Windows Server Microsoft server technology Computer access control Internet security