Abstract: Technologies and techniques for monitoring a communication bus. A number of electronic stations are networked by the communication bus. During operations, the messages transmitted via the communication bus are identified via an identifier, it being determined for each station which messages each station can send with which identifier. According to a uniqueness rule, it is prohibited for another station to send a payload message with an identifier that is already reserved for this station. In order to expose stations that introduce manipulated messages onto the communication bus, a protocol unit in a station maintains a list of the identifiers of the messages actually sent by the station. The attacker station can be identified via subsequent comparisons with this list.