A device blocking tool includes a user interface, a location engine, and a connection engine. The user interface receives at least one of a MAC address of a device and an IP address of the device. The location engine communicates a query to an access control server, receives a response, and determines, based on the response, that the device connected to a network through a wired connection. In response to a determination that the device connected through the wired connection, the location engine determines a switch through which the device connected. The location engine also determines a VLAN through which the device connected and determines, based on a type associated with the VLAN, that the device is an IP telephone. The connection engine connects to the determined switch in response to the determination that the device connected through the wired connection.