Network data communication system

A network data communication system for a network data communication, comprising:

• a first computer connected to a first network;
• a second computer connected to a second network;
• and
• a third computer connected to both of said first and second networks for establishing communication thereinbetween,
• wherein said third computer includes a communication proxy having a proxy registration table and a communication proxy process for receiving a communication packet addressed to said second computer,
• wherein said proxy registration table contains a network address of said second computer and communication parameters designating a communication method to be employed in communication between said communication proxy process and said second computer,
• wherein said third computer searches said proxy registration table when a communication packet which is not addressed to said third computer is received, and
• wherein when a destination network address of the communication packet is registered in said proxy registration table, the communication proxy process receives the communication packet and transmits the communication packet to the destination according to the communication method designated by said communication parameters registered in said proxy registration table.