Network address translation system and method being capable of accessing to node having private IP address from external network and computer-readable medium recording the method

摘要

PURPOSE: A network address conversion system and method for access to a node having a private IP address from an external network is provided to achieve access from an Internet external network node to a private network node having a private IP address. CONSTITUTION: A network address conversion system(40) is comprised of an input unit(42), a reservation unit(44), a port value allocation unit(46), a mapping table(48), an address conversion unit(50), and an output unit(52). The reservation unit(44) receives an access reservation or access cancellation from an external network node for a specific node of a private network. If the access reservation for the specific private network node is received, the reservation unit(44) requests the port value allocation unit(46) to allocate an external port value. The port value allocation unit(46) allocates an external port value to the specific private network node requested from the reservation unit(44) and stores the correspondence relationship in the mapping table(48). In the case of carrying out the transmission and reception of data between an external network node and the specific private network node using the external port value, the address conversion unit(50) converts the external port value into the specific node's private IP address.