Method and system for detecting and preventing access intrusion in a network

A wireless computer network includes components cooperating together to prevent access intrusions by detecting unauthorized devices connected to the network, disabling the network connections to the devices, and then physically locating the devices. The network can detect both unauthorized client stations and unauthorized edge devices such as wireless access points (APs). The network can detect intruders by monitoring information transferred over wireless channels, identifying protocol state machine violations, tracking roaming behavior of clients, and detecting network addresses being improperly used in multiple locations. Upon detecting an intruder, the network can automatically locate and shut off the physical/logical port to which the intruder is connected.