Patent ID: 8037161

Claim:
A network system in which a plurality of network devices are connected to a network, wherein each of the plurality of network devices includes: a peripheral device information collection unit which collects peripheral device information indicating which ones of the network devices are connected to the network while the connection to the network is established; a peripheral device information storage unit which stores home network information, which is a chronological list of network devices connected to the network, in accordance with the collected peripheral device information; a peripheral device information transmission unit which transmits the home network information stored in the peripheral device information storage unit in compliance with a request from another network device; a peripheral device information reception unit which requests the other network device to deliver the home network information stored therein and receives the delivered home network information; and a peripheral device information collation unit which collates the home network information received from the other network device through the peripheral device information reception unit with the home network information stored in the peripheral device information storage unit and judges whether the other network device belongs to the same network as the local network device.