Communication system for processing a request message sent from a mobile radio terminal (101) of a mobile radio communication network (100) to a message filter processor (102,103,104), in which the message filter processor (102,103,104) is set up to,
- detect a request message, which is present in the form of a data packet (300), having a packet header (301) and user data (302), in which one or more electronic peer-to-peer files is/are requested, detection of the request message including reading data in the packet header (301) of the request message and the data being used to identify a specific peer-to-peer application,
- use the request message to create a peer-to-peer request message according to a predefined peer-to-peer communication protocol, and
- send the peer-to-peer request message to at least one processor (201 . . . 207) in a fixed network communication network (200).