Abstract: A method of detecting and filtering illegitimate communication streams in a satellite communication network is provided, the method being executed by a gateway satellite station able to establish a communication link between a satellite and an access network and comprising the steps of: receiving a communication stream originating from the satellite, determining a set of characteristics of the communication stream forming a signature of the stream, applying at least one classification algorithm so as to class the signature into a set of legitimate signatures or into a set of illegitimate signatures, if the signature is classed into the set of illegitimate signatures, filtering the communication stream, otherwise transmitting the communication stream to the access network.