TCP RELAY DEVICE

PROBLEM TO BE SOLVED: To provide a TCP relay device for terminating and relaying TCP between a mobile phone and a server, performing detailed control on the basis of each TCP connection unit, by default TCP transmission control with the server and TCP transmission control with a mobile phone suitable for radio, with easy setting for determining a network type to which a communication destination terminal belongs.SOLUTION: The TCP relay device comprises: means for enabling setting of TCP control information according to the characteristic of the network on the basis of the TCP connection unit; from an application side, means for enabling instructing to set TCP control information according to the network type to which the communication destination terminal is connected; and means for determining the network type, to which the communication destination terminal is connected, by a passive connection to a waiting port or a TCP connection to the server device.