Patent ID: 8103954

Claim:
A proxy server constituting a communication system having a client terminal, the proxy server and a web server, said proxy server comprising: a web page data receiving device for receiving web page data transmitted from the web server and to which cookie information has been appended, based upon a request from the client terminal; a link destination URL converting device for converting a link destination URL linking to a second web page, which URL is contained in a first web page represented by the web page data received by said web page data receiving device, in such a manner that the link destination URL becomes a URL that differs for every conversion; a web page data transmitting device for transmitting web page data, which represents the first web page containing the link destination URL obtained as a result of the conversion by said link destination URL converting device, to the client terminal; a first storage control device for controlling a first storage device in such a manner that the link destination URL obtained as a result of the conversion by said link destination URL converting device and client identification data generated based upon the request from the client terminal are stored in correspondence with each other; a second storage control device for controlling a second storage device in such a manner that the client identification data and cookie information, which has been appended to the web page data received by said web page data receiving device and which is updated every time it is received, are stored in correspondence with each other; a URL reverse-converting device for restoring the link destination URL linking to the second web page to the link destination URL that prevailed before the conversion by said link destination URL converting device, in accordance with a request for the second web page specified by the link destination URL contained in the first web page, this request being transmitted from the client terminal in response to transmission thereto of the web page data by said web page data transmitting device, and for finding client identification data that has been stored in the first storage device in correspondence with the URL that was obtained as a result of the conversion by said link destination URL converting device; a cookie information detecting device for finding cookie information, which has been stored in the second storage device, from the client identification data found by said URL reverse-converting device; a request-data transmitting device for transmitting request data, which requests the second web page specified by the URL restored as a result of the reverse conversion by said URL reverse-converting device, to the web server upon appending the cookie information found by said cookie information detecting device; and a memory device including at least one of the first storage device and the second storage device.