Abstract: Described is a method of identifying a home network of a user, for example, a roaming user connecting using a Wi-Fi connection, for example, via a wireless router, based on a user identification received by a first device of the network visited by the user. If the authentication device of the visited network cannot determine the home network of the user based on the user identification, then it queries a core platform, which may be outside the first network. The core platform queries nodes associated with possible home networks and, based on the responses received from the nodes, determines the home network of the user. The user can then be authenticated using the home network information.