A method sets up a local control channel between a control unit for controlling a building-internal electrical component, connected to a building-internal access portal, and the access portal, by authenticating the control unit against a building-external authentication server via a building-external communication network; transmitting a network address of the building-internal access portal using the building-external authentication server to the control unit upon successful authentication of the control unit against the building-external authentication server via the building-external communication network; transmitting an access authorization for the building-internal access portal to the control unit using the building-external authentication server via the building-external communication network upon successful authentication of the control unit against the building-external authentication server via the building-external communication network; and setting up the local control channel between the control unit and the building-internal access portal in response to receiving the network address of the building-internal access portal and the access authorization.