Patent ID: 8446874

Claim:
A packet filtering method in a packet filtering apparatus of a network system using Mobile Internet Protocol (IP), the method comprising: determining if a next header of a packet received from a correspondent node (CN) is a routing header type; determining if a home address included in the routing header type is identical to a destination address stored in a packet filter rule, if the next header of the packet is the routing header type; determining if the next header of the packet is a mobility header, if the home address included in the routing header type is the destination address stored in the packet filter rule; determining if a binding response message is received, if the next header of the packet is the mobility header; determining if the CN has successfully received a binding update according to a status field value of the binding response message; adding a Care-of Address (CoA) carried on the destination address of the received packet to the packet filter rule as a candidate destination address, if the CN has successfully received the binding update; and maintaining a current packet filter rule, if the CN has not successfully received the binding update, wherein the packet filter rule is stored in the packet filtering apparatus and is applied to a result of analyzing packet header regions.