Abstract: The disclosure relates to a motor vehicle with a vehicle internal data network through which control devices of the motor vehicle are coupled with each other for exchanging messages. The invention provides that the data network is subdivided into a plurality of security zones, within each of which at least one of the control devices is arranged, and domain controllers are provided, each separating at least two of the security zones and adapted to transmit at least one of the messages between at least two of the security zones separate from it if the message meets a predetermined safety criterion and to block the transmission of the message if the safety criterion is violated.

Abstract: At a first port of a switch device of a motor vehicle, a device identifier of a device of the motor vehicle is received. An authenticity test on the basis of the device identifier is performed. If a test result of the authenticity test is positive, communication data of the device addressed to at least one further device of the motor vehicle are received at the first port and transmitted in a first VLAN of a communication network of the motor vehicle to the at least one further device. If the test result is negative, the communication data are rejected at the first port. A diagnostic inquiry for the device is received from a diagnostic device at a second port of the switch device. Independently of the test result the diagnostic inquiry is forwarded via the first port to the device in a second VLAN of the communication network.

Abstract: At a first port of a switch device of a motor vehicle, a device identifier of a device of the motor vehicle is received. An authenticity test on the basis of the device identifier is performed. If a test result of the authenticity test is positive, communication data of the device addressed to at least one further device of the motor vehicle are received at the first port and transmitted in a first VLAN of a communication network of the motor vehicle to the at least one further device. If the test result is negative, the communication data are rejected at the first port. A diagnostic inquiry for the device is received from a diagnostic device at a second port of the switch device. Independently of the test result the diagnostic inquiry is forwarded via the first port to the device in a second VLAN of the communication network.