An arrangement to direct a packet sent out from an arbitrary apparatus connected to a network to a predetermined authentication server without changing the configuration of a computer network. A packet transmitted from apparatus, such as a personal computer, newly connected to the network, is guided to an authentication server via communication control apparatus. The communication control apparatus replaces a MAC address of the destination addresses of another server, which is included in the ARP cache of the personal computer, with the MAC address of the communication control apparatus to guide the packet from the personal computer to the communication control apparatus. The communication control apparatus further transmits the received packet to a predetermined authentication server.