Patent ID: 8036232

Claim:
A network system using Mobile Internet Protocol (IP), the system comprising: a mobile node for transmitting a packet including information indicating that the packet is capable of passing a packet filter rule; and a packet filtering apparatus for determining whether an address included in the information is identical to a source address stored in the packet filter rule, and determining whether to pass the packet according to a result of the determination, wherein the packet filtering apparatus comprises: a next header reader for reading a next header of the received packet to determine whether it is a mobility header; a mobility header type reader for reading a mobility header type when the next header is the mobility header; a mobility option reader for reading a mobility option added by the mobile node; and a packet rule applier for determining whether a home address included in the mobility option read by the mobility option reader is identical to a source address stored in the packet filter rule, and determining whether to pass the packet according to a result of the determination from packet rule applier.