Patent ID: 7457293

Claim:
A communication apparatus connectable to a network including the Internet, the communication apparatus comprising: a global address information acquiring section for communicating with a server in the network and acquiring information on an address in the Internet assigned to the communication apparatus as first global address information; a WAN-side address information acquiring section for acquiring information on a WAN-side address assigned to a router directly connected to the communication apparatus as first WAN-side address information; a local address information acquiring section for acquiring information on an address in a local area network assigned to the communication apparatus as first local address information; an address information notification section for notifying the first global address information, the first WAN-side address information, and the first local address information to a communication partner apparatus desiring to perform peer-to-peer (P2P) communication via the server in the network; and an address information acquiring section for acquiring, via the server in the network, second global address information which is information on an address in the Internet assigned to the communication partner apparatus, second WAN-side address information which is information on a WAN-side address assigned to a router directly connected to the communication partner apparatus, and second local address information which is information on an address in a local area network assigned to the communication partner apparatus, wherein the communication apparatus determines a method by which P2P connection can be established based on the first and second global address information, the first and second WAN-side address information, and the first and second local address information.