Communication terminal, communication system, communication terminal control method, and program

A communication terminal comprising:

• a first normal operation determination unit configured to determine whether or not an external communication network relay device, which requests an authentication device to authenticate communication terminals, is operating normally;
• a terminal selection unit configured to, when the first normal operation determination unit determines that the external communication network relay device is not operating normally, select, from among a plurality of communication terminals including the own communication terminal, a substitute communication terminal for executing a first substitute process for the external communication network relay device;
• a first instruction unit configured to, when the own communication terminal is selected as the substitute communication terminal, instruct an internal wireless communication network relay device, which is a relay destination for data from the plurality of communication terminals, to perform processes of
• relaying a connection information allocation request from a requesting communication terminal and a response to the allocation request between the requesting communication terminal and the own communication terminal,
• relaying data relating to authentication of the requesting communication terminal between the own communication terminal and the authentication device, and
• relaying data for the external communication network from the requesting communication terminal to the external communication network via the own communication terminal;
• and
• a second instruction unit configured to instruct a bypassing relay device that relays the data for the external communication network between the internal wireless communication network relay device and the external communication network to further perform a process of relaying the data relating to authentication between the internal wireless communication network relay device and the authentication device.