Abstract: It is so arranged that when a client terminal communicates with a content server via a proxy server, the history of such communication can be ascertained. A request for a menu page is transmitted from the client terminal to the proxy server. A link to the content server has been embedded in the menu page. Data representing the menu page in which the URL of this link destination has been converted is transmitted to the client terminal. If the web page at the link destination that has been embedded in the menu page is requested by the client terminal, the proxy server restores the URL to the URL that prevailed before the conversion and requests the content server for the web page. The web page requested from the client terminal is stored in the proxy server. Thus, even if the client terminal requests the web pages of a plurality of content servers, the history thereof can be ascertained.