Method and Apparatus for Performing Network Address Translation

An embodiment of the invention is a method and corresponding system for improved network address translation (NAT) operation, to enable efficient translation for packets destined for communication systems within a domain utilizing network addresses that are incompatible with source and destination addresses indicated in packets delivered from the global Internet. Since the addresses are not compatible with global Internet addresses, delivery cannot be accomplished except by some method of address translation. Traditional systems have not been constructed to enable such inbound translations, providing, instead, only communication outbound from the incompatibly addressed domain towards the global Internet. The example embodiment employs history and pattern matching between observable characteristics of the inbound payload, associated over time with specific destinations. The example embodiment may also employ DPI search techniques known from widely deployed systems in use today, to identify a field on which the pattern matching may operate.