Patent ID: 7633948

Claim:
A relay device for relaying a data packet between a first network and a second network each being part of a same local area network (LAN), said relay device comprising: a first interface; a second interface; and a control portion capable of performing port forward setting, wherein, when the first interface is connected to a third network through a relay of the first network and the second interface is connected to a terminal device of the second network, and when the relay device receives a port forward request from the terminal device, the control portion sends a port forward setting request to the relay to request the relay to create a port number relation between a port number of the relay and a port number of said relay device, and the control portion creates a port number relation between the port number of said relay device and a port number of the terminal device, wherein the control portion receives the data packet transferred by the relay to said relay device using the relation between the port number of the relay and the port number of said relay device, and transfers the received data packet using the relation between the port number of said relay device and the port number of the terminal device.