Control method for authentication of a connection device connected to a network (N), in particular a network (N) mounted on a boat , comprising the steps of: performing an authentication-free determination (S3) to determine whether or not the connection device corresponds to an authentication-free device, performing an authenticating action (S4 to S6) with the connection device if the connection device does not correspond to an authentication-free device (No at S3), and exempting the connection device from the authenticating action (S4 to S6) if the connection device corresponds to an authentication-free device (Yes at S3), wherein the connection device is instructed to transmit an address requesting message (M) before the authentication-free determination (S3) is performed, wherein the connection device connected to the network (N) is a gage and/or a gateway and/or a remote control and/or an immobilizer and/or a multi-function sensor , and the address requesting message (M) comprises an identification field (F1) comprising priority (P) and/or communication identification (PGN) and/or destination address (DA) and/or source address (SA), and the address requesting message (M) comprises a data field (F2) comprising manufacturer code and/or device classes and/or device functions, wherein in the authentication-free determination, it is determined whether or not the connection device corresponds to an authentication-free device based on a manufacturer code in the address requesting message (M) while defining the authentication-free device to be a connection device manufactured by a specific manufacturer representing the manufacturer of the connection device or corresponds to an authentication-free device based on based on a device class contained in the address requesting message (M) while defining the authentication-free device to be a connection device belonging to a specific device class. performing an authentication-free determination (S3) to determine whether or not the connection device corresponds to an authentication-free device, performing an authenticating action (S4 to S6) with the connection device if the connection device does not correspond to an authentication-free device (No at S3), and exempting the connection device from the authenticating action (S4 to S6) if the connection device corresponds to an authentication-free device (Yes at S3), wherein the connection device is instructed to transmit an address requesting message (M) before the authentication-free determination (S3) is performed, wherein the connection device connected to the network (N) is a gage and/or a gateway and/or a remote control and/or an immobilizer and/or a multi-function sensor , and the address requesting message (M) comprises an identification field (F1) comprising priority (P) and/or communication identification (PGN) and/or destination address (DA) and/or source address (SA), and the address requesting message (M) comprises a data field (F2) comprising manufacturer code and/or device classes and/or device functions, wherein in the authentication-free determination, it is determined whether or not the connection device corresponds to an authentication-free device based on a manufacturer code in the address requesting message (M) while defining the authentication-free device to be a connection device manufactured by a specific manufacturer representing the manufacturer of the connection device or corresponds to an authentication-free device based on based on a device class contained in the address requesting message (M) while defining the authentication-free device to be a connection device belonging to a specific device class. <EOS>