A procedure for operating a communication network including a network device that is in communication in the network with at least one user communication terminal and at least one server that server that provides content. The procedure includes receiving a message from one of the user communication terminal and the server, inserting at least one of an identifier of the user communication terminal and an identifier of the server in the message, and forwarding the message, including the at least one identifier inserted in the inserting, towards another of the user communication terminal and the server. A computer program, apparatus, and communication network also operate in accordance with the procedure.