Abstract: A method and device for detecting and halting specified peer-to-peer (“P2P”) and/or Internet Relay Chat (“IRC” communication sessions based on a priori defined templates is described. Network packets are intercepted and inspected for patterns (defined by the templates) that identify them as definitely, likely or not being associated with one of the specified P2P and/or IRC protocols. Those packets identified as definitely belonging to one of the specified protocols are prevented from reaching their target destination. Those packets identified as only likely belonging to one of the specified protocols are permitted to continue toward their target destination after select information about the particular session/packet is recorded for later use. Those packets identified as not belonging to one of the specified protocols are permitted to continue to their target destination.