Patent ID: 7886078

Claim:
A communication apparatus having a connection support server function, which is, in a network including a plurality of subnetworks connected via a plurality of network address translation (NAT) devices, connected to an arbitrary subnetwork in the network and which has an established communication path with another communication apparatus connected to a different subnetwork that is different from the arbitrary subnetwork to which the communication apparatus having the connection support server function is connected, the communication apparatus having the connection support server function comprising processor including: a relay request transfer section for, when receiving from an arbitrary communication apparatus a relay request for an apparatus detection request, transferring to the another communication apparatus the relay request for the apparatus detection request; and an apparatus detection response transfer section for, when receiving an apparatus detection response, transferring the received apparatus detection response to the arbitrary communication apparatus which is a transmission source of the relay request for the apparatus detection request, wherein when receiving the relay request for the apparatus detection request, the relay request transfer section transfers the relay request for the apparatus detection request, to the another communication apparatus connected to the different subnetwork that is different from a subnetwork to which the arbitrary communication apparatus which is the transmission source of the relay request for the apparatus detection request is connected, the apparatus detection response transfer section has the connection support server function for, when receiving the apparatus detection response from the another communication apparatus to which the relay request for the apparatus detection request has been transferred, transferring the received apparatus detection response to the arbitrary communication apparatus which is the transmission source of the relay request for the apparatus detection request, and the communication apparatus having the connection support server function is the only apparatus on the network including the plurality of subnetworks that transfers the relay request for the apparatus detection request from the arbitrary communication apparatus to communication apparatuses on subnetworks of the network that are different from the subnetwork to which the arbitrary communication apparatus is connected.