A local identity management module is described that is able to identify each of a plurality of user devices. The user devices communicate with the outside world via a network address translation device that converts an internal address of the user devices to a single internet protocol address, typically the internet protocol address of the network address translation device. An external identity management system can communicate with the local identity management module in order to identify which of said plurality of user devices made a particular request and, in some embodiments, to identify a user of said user device.