A locking system for a building door, having at least - a locking device, e.g. a motorised lock, - a controller with at least one receiver for receiving an opening signal by radio, - a communication unit, in the form of a network server, which is situated within range of the controller and is integrated in a local radio network and also has a transmitter for transmitting an opening signal by radio to the receiver of the controller, and - at least one terminal which operates as a network client and is logged into the communication unit and is configured to transmit an opening command to the communication unit as a result of an action of a user, the communication unit being configured thereupon to transmit an opening signal to the controller, characterised in that an actuation device with a transmitter for transmitting an actuation signal to the controller is provided in the region of the building door, wherein the communication unit is configured to actuate the locking device, e.g. to unlock the lock, using the controller as a result of the action of the user on the terminal only when an opening command has been transmitted to the communication unit and an actuation signal has been transmitted from the actuation device to the controller and an actuation signal has been transmitted from the controller to the communication unit, wherein the communication unit is configured to carry out a check of an AND operation of the opening command and the actuation signal. - a locking device, e.g. a motorised lock, - a controller with at least one receiver for receiving an opening signal by radio, - a communication unit, in the form of a network server, which is situated within range of the controller and is integrated in a local radio network and also has a transmitter for transmitting an opening signal by radio to the receiver of the controller, and - at least one terminal which operates as a network client and is logged into the communication unit and is configured to transmit an opening command to the communication unit as a result of an action of a user, the communication unit being configured thereupon to transmit an opening signal to the controller, characterised in that an actuation device with a transmitter for transmitting an actuation signal to the controller is provided in the region of the building door, wherein the communication unit is configured to actuate the locking device, e.g. to unlock the lock, using the controller as a result of the action of the user on the terminal only when an opening command has been transmitted to the communication unit and an actuation signal has been transmitted from the actuation device to the controller and an actuation signal has been transmitted from the controller to the communication unit, wherein the communication unit is configured to carry out a check of an AND operation of the opening command and the actuation signal. characterised in that an actuation device with a transmitter for transmitting an actuation signal to the controller is provided in the region of the building door, wherein the communication unit is configured to actuate the locking device, e.g. to unlock the lock, using the controller as a result of the action of the user on the terminal only when an opening command has been transmitted to the communication unit and an actuation signal has been transmitted from the actuation device to the controller and an actuation signal has been transmitted from the controller to the communication unit, wherein the communication unit is configured to carry out a check of an AND operation of the opening command and the actuation signal.