Abstract: A system is provided for filtering packets. The system includes: a filter for determining, by applying a set of at least one filtering rule, whether a packet is permitted to be routed towards a receiving entity. The system includes a verification element for verifying validity of an authentication token included in a request received by the filtering system and adds, to the set, after receiving an initial request, a so-called top-level filtering rule, permitting the routing, towards the verification element, of at least one packet received via a predetermined communication port of the device, in which the source address is identical to the source address of the initial request, regardless of the source communication port of the subsequent request. A routing element routes a subsequent request including a valid authentication token towards a receiving entity of the subsequent request.