Abstract: To reduce a load inflicted on a network by peer-to-peer communication between terminals, the present invention provides a network system having a communication destination machine and a communication source machine, in which: the communication destination machine includes a unit which registers its own location information in a peer-to-peer network; and the communication source machine includes: a unit which searches the peer-to-peer network for the location information of the communication destination machine and obtains the location information; and a unit which uses the obtained information to establish peer-to-peer communication. The location information contains communication path information which enables the communication source machine to communicate with a desired machine beyond a path controller, and a parameter necessary for communication. The communication source machine may include a unit which accumulates location information or similar data of multiple communication destination machines.