A network system includes: a hub base that includes a first network device with a hub function, the first network device being connected to an information communication network; and a spoke base that includes a second network device without the hub function, the second network device being connected to the information communication network. Communication between a computer provided in the spoke base and an external device connected with the computer via Internet is performed such that intra-network loopback communication is performed between the first network device and the second network device in the information communication network without an internet service provider, and communication is performed between the first network device and the external device via the internet service provider.