Apparatus for being shared ip address by port number

PURPOSE: An apparatus for sharing an IP address is provided to prevent the waste of the IP address and improve the speed by using port number included in a TCP/UDP/IP header. CONSTITUTION: The first physical class module(2) is connected with the Internet(8). In addition, the first physical class(2) performs a conversion between a transmission media signal and Ethernet data. The second physical class module(3) is connected with a communication module of a PC(9). In addition, the second physical module(3) performs a conversion between a physical class signal and the Ethernet data. The third physical class module(4) is connected with hardware for a specific application. In addition, the third physical class module(4) performs a conversion between the physical class signal and the Ethernet data. A transmission module(5) transmits the data inputted from the second and the third physical class module(3,4) according to the order of priority of port number. A port number storing device(7) stores a port number of the hardware for the specific application connected with the third physical class module(4). A receiving module(6) judges an object port and transmits the object port to the communication module of the PC(9) or the hardware for the specific application through the second of the third physical class module(3,4).