A communication apparatus includes a global address information acquiring section for acquiring first global address information, a WAN-side address information acquiring section for acquiring first WAN-side address information, and a local address information acquiring section for acquiring first local address information. Moreover, the apparatus includes 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. Furthermore, the apparatus includes an address information acquiring section for acquiring second global address information, a second WAN-side address information, and a second local address information assigned to the communication partner apparatus. 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.