Patent ID: 7406079

Claim:
A repeater which passes on a communications packet between a first network and a second network, the repeater comprising: a port number setting section which sets an external port number on the first network for a terminal connected to the second network, in response to an access from the terminal; a port mapping table where the set external port number is stored so as to be associated with an internal IP address and an internal port number of the terminal connected to the second network; a controller, which, receiving a communications packet to which the external port number is specified, converts the external port number to the internal port number based on the port mapping table and transfers the communication packet to the second network using the internal port number; a timer, which counts an unoccupied time of the external port number by starting to count the external port number is stored in the port mapping table; and a port manager, which, when the unoccupied time of the external port has reached a predetermined time, automatically deletes registration of the external port number that is elapsed in the predetermined time from the port mapping table.