1. A security system for use in a communications network, said network comprising means to allow a plurality of devices to communicate over the network wherein at least one device is a machine to machine (M2M) operated device and at least one other device is a human operated device, said security system comprising: means to capture data traffic originating from the plurality of devices on the network; means for analysing the data traffic; and means for identifying at least one of the M2M operated devices on the network, wherein the system is configured to dynamically adapt to different data traffic patterns on the network.