A device identification server identifies a “household” to which a particular device belongs by associating the device with a LAN MAC address of the router through which the device connects to a wide area network such as the Internet because the LAN MAC address (i) is unique to the router and (ii) is not readily discoverable by interaction with the router through the wide area network, impeding spoofing by malicious entities. The device queries and receives the LAN MAC address of the router through the local area network. The device passes the LAN MAC address of the router along with its digital fingerprint to the device identification server. Devices that report the same LAN MAC address of the router through which they connect to the wide area network are determined to be from the same “household”, i.e., to be managed by one and the same entity.