A computer network system in which an IP address is assigned not only automatically at a destination of a notebook size PC (portable personal computer) 4, but also information relating to shared resources on the network is obtained at the site from a server 1 through a LAN circuit 2, so that the notebook size PC 4 can be used by connecting to the network even in the absence of the administrator. Henceforth, when the user moves within the same building as his own office, it seems that the occasion of using the portable personal computer by connecting to the network such as the Internet and intranet increases. In such a case, connection and disconnection of the network may be repeated frequently, and setting for such operation is facilitated.