Patent ID: 8024435

Claim:
A router, comprising: an internet protocol (IP) address searching module operable to broadcast a dynamic host configuration protocol (DHCP) discover packet over a network so as to search a private IP address of a modem connected with the router; a packet receiving module operable to receive a DHCP offer packet from the modem, wherein the DHCP offer packet comprises the private IP address of the modem; an IP address obtaining module operable to obtain the private IP address of the modem from the DHCP offer packet; an IP address configuration module operable to configure IP addresses of a wide area network (WAN) port and a local area network (LAN) port of the router according to the private IP address of the modem, so as to allow the private IP address of the modem to be in the same network segment with the IP address of the WAN port but in different network segments with the IP address of the LAN port; a storage system that stores an IP addresses list that records a plurality of IP addresses; a determining module operable to determine whether a broadcast count of broadcasting the DHCP discover packet equals to a predetermined value upon the condition that there is no reply from the modem responding to the DHCP discover packet, so that the IP address searching module broadcasts the DHCP discover packet one more time upon the condition that the broadcast count is less than the predetermined value; a list acquisition module operable to acquire the IP address list from the storage system upon the condition that the broadcast count equals to the predetermined value; an IP address verification module operable to broadcast a plurality of address resolution protocol (ARP) packets via the network to verify if one of the IP addresses recorded in an IP address list is the private IP address of the modem; and a processor that executes the IP address searching module, the packet receiving module, the IP address obtaining module, and the IP address configuration module.