Method and system for simulating network address translation

A system for simulating NAT (network address translation) performed in an internet protocol (IP) sharing device, comprising:

• a client application generating packets to be forwarded to an external network;
• a network interface linking the IP sharing device with the external network;
• a Network Driver Interface Specification (NDIS) interface hooking packets incoming from the external network;
• and
• a NAT unit having a mapping table and performing a network address translation on the hooked packets with reference to the mapping table, wherein the mapping table identifies IP addresses and port numbers of the packets to be translated by the NAT unit.

A method of simulating NAT (network address translation) performed in an internet protocol (IP) sharing device selectively operable in one of different network address translation (NAT) schemes by using a mapping table which identifies IP addresses and port numbers of packet to be translated by the IP sharing device, the method comprising:

• updating the mapping table depending on the one of different NAT schemes to be selectively operable by the IP sharing device;
• hooking a packet from an application program;
• performing the NAT of IP address and port number of the hooked packet with reference to the mapping table;
• and
• forwarding the packet to the translated IP address and port number.