The wireless activity in a geographic area containing LAN connection ports is monitored using one or more sensor devices, called sniffers. By analyzing said wireless activity, one or more APs that are operating in said geographic area are identified. The active APs so identified are classified into three categories, namely “authorized” APs (those that are allowed by network administrator), “unauthorized” APs (those that are not allowed by the network administrator, but are still connected to the LAN of interest) and “external” APs (those that are not allowed by network administrator but are not connected to the LAN of interest, for example APs connected to the neighbor's LAN) by conducting one or more tests. The sniffers detect any wireless station attempting to connect to or communicating with the one or more identified unauthorized APs. Upon identifying unauthorized AP and/or intruding wireless station an indication is transferred to the prevention process.