Patent ID: 7508826

Claim:
A method for translating an address of a packet transmitted and received between a client and a server which are connected to each other through a proxy server, the method comprising: receiving a request packet, which has a source address translated into the address of said proxy server, output from said client to said server via said proxy server, and analyzing contents of said request packet to acquire the address of said client; translating said source address of said request packet into the acquired address of said client and transmitting said request packet to said server; receiving a response packet in response to said request packet from said server, translating a destination address of said response packet from the address of said client into the address of said proxy server, and transmitting said response packet to said proxy server; after the address of said client is acquired, generating a communication identifier capable of uniquely identifying said request packet; translating a source communication identifier of said request packet into the generated communication identifier, at the same time that the source address of said request packet is translated; when the source address of said request packet and said communication identifier are translated, storing contents of said source address and said source communication identifier that are to be translated and contents of said source address and said source communication identifier that are translated, in association with each other in a database; and when said response packet is received, referring to said database to determine the address of said client to be set as said destination address, and translating a destination communication identifier of said response packet into said source communication identifier to be translated which is registered in said database.