NAT DEVICE, TCP COMMUNICATION METHOD, COMMUNICATION PROGRAM, AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a NAT (network address translation) device which is possible to perform communication of a protocol including information of IP addresses and port numbers such as FTP (file transfer protocol) or H.323 inside of a packet. SOLUTION: The NAT device positions between a device belonging to a private address space and a device belonging to a global address space. When the NAT address establishes a TCP (transmission control protocol) session between the device belonging to the private address space and the device belonging to the global address space, it is provided with a 1st means which creates a mapping table for address translation corresponding to the private address of the device belonging to the private address space to an arbitrary global address in the global addresses held in the NAT device, a 2nd means which holds the mapping table until a constant time elapses from the time of completion of the TCP, and a 3rd means which deletes the mapping table after the predetermined time elapses. COPYRIGHT: (C)2004,JPO