Patent ID: 7281059

Claim:
A method for using an IP address on a LAN including a router and a LAN device, performed in the router, comprising: upon receipt of a unique IP address request from the LAN device, allocating a non-used unique IP from a dynamic unique IP address pool having a plurality of unique IP addresses to the LAN device, and storing the allocated unique IP address corresponding to a LAN IP address of the LAN device in a unique IP address allocation table; upon receipt of a packet from the LAN device, determining whether the origination party's IP address of the packet is registered in the unique IP address allocation table; when the origination party's IP address is not registered in the unique IP address allocation table, changing the origination party's IP address of the packet to a unique IP address of the router to transmit the packet to the Internet; when the origination party's IP address is registered in the unique IP address allocation table, changing the origination party's IP address of the packet to a unique IP address corresponding to the origination party's IP address, to transmit the packet to the Internet; and when the allocated unique IP address is returned from the LAN device, adding the allocated unique IP address returned from the LAN device to the dynamic unique IP address pool, and deleting the returned unique P address and its corresponding LAN IP address in the unique IP address allocation table.