Network system, access-support server, processing device, and communication agent device

A network system comprising:

• a first device configured to perform processing;
• a second device configured to cause the first device to perform the processing, the second device being an application server running an application software for the first device;
• a third device located in a same network as that of the first device;
• and
• a server configured to support the second device in having access to the first device;
• the first device, the second device, the third device and the server being connected to a first communication network, wherein the third device is connected to the first communication network through a second communication network including a firewall, wherein
• the third device includes a first session establishing portion configured to have access to the server and to establish a first tunnel session encapsulated in accordance with a protocol thereof between the third device and the server,
• the second device includes an address information transmission portion configured to send, to the server, address information indicating an address of the second device,
• the server includes a transfer portion configured to transfer the address information through the first tunnel session to the third device,
• the third device further includes a second session establishing portion configured to have access to the second device based on the address information and to establish a second tunnel session encapsulated in accordance with a protocol thereof between the third device and the second device, and
• the third device further includes a relay portion configured to relay, through the second tunnel session, data sent and received between the first device and the second device.

A processing device for performing processing, the device comprising:

• a first session establishing portion configured to have access to a server and to establish a first tunnel session encapsulated in accordance with a protocol thereof between the processing device and the server, the server supporting an external device located in a first communication network, wherein the processing device is connected to the first communication network through a second communication network including a firewall, and the external device is an application server running an application software for the processing device;
• a receiving portion configured to receive address information indicating an address of the external device from the server through the first tunnel session;
• and
• a second session establishing portion configured to have access to the external device based on the address information and to establish a second tunnel session encapsulated in accordance with a protocol thereof between the processing device and the external device.

A communication agent device located and used in a network together with a processing device for performing processing, the communication agent device comprising:

• a first session establishing portion configured to have access to a server and to establish a first tunnel session encapsulated in accordance with a protocol thereof between the communication agent device and the server, the server supporting an external device located in a first communication network, wherein the communication agent device is connected to the first communication network through a second communication network including a firewall, and the external device is an application server running an application software for the processing device;
• a receiving portion configured to receive address information indicating an address of the external device from the server through the first tunnel session;
• a second session establishing portion configured to have access to the external device based on the address information and to establish a second tunnel session encapsulated in accordance with a protocol thereof between the communication agent device and the external device;
• and
• a relay portion configured to relay, through the second tunnel session, data sent and received between the processing device and the external device.