One of the users in our company turned on bridging on his XP laptop and connected to both the wireless and the hard wired ethernet connection. Within half an hour, his PC which was now acting as a mini router, had bridged the two networks and shut down over 900 people. The wireless stopped working totally. The only way we fixed it was to find him, and have him turn off the bridging. Is there any way to tell our Cisco switches to shut down his port when the PC is using bridging?