A method and a system for service-based authentication of a terminal to a network is described, wherein the terminal comprises a number of communications interfaces, each communications interface allowing the terminal to set-up a predetermined communication channel with the network. The method comprises the steps of: sending a service request for access to a network service; receiving in response to the service request an authentication request from the network; identifying the communication channel through which the authentication request was received; and, sending an authentication response RES to the network, wherein the authentication response depends on the identified communication channel.