A network configuration process establishes, between an access point device and a client terminal, a wireless communication link through a first encrypted communication requiring no authentication process, and sends authentication data from the access point device to the client terminal in a state where the wireless communication link through said first encrypted communication is established. The link through the first encrypted communication is discarded in response to sending of the authentication data. Then, a second link is established through a second encrypted communication that requires an authentication process using the sent authentication data, where the first link is continually discarded.