Communication device, communication method, and communication system

A communication method executed by a computer included in communication device connected to a first network and a second network, said communication device including a first communication port for physically connecting with a first device on the first network through a first local area network cable, and a second communication port for physically connecting with a second device on the second network through a second local area network cable, said first network having a first network address, and the second network having a second network address that is different from the first network address, the communication method comprising:

• storing, within the communication device, connection confirmation information including identification information of the first device on the first network for permitting the first device to connect via the first communication port and identification information of the second device on the second network for permitting the second device to connect via the second communication port;
• and
• preempting a relay between the first network via the first communication port and the second network via the second communication port upon detecting that the identification information of the first device is not received from the first communication port and that the identification information of the second device is not received from the second communication port based on the connection confirmation information.

A communication system comprising:

• a communication device connected to a first network and a second network;
• an image processing device connected to the first network;
• and
• an information processing device connected to the second network, said first network having a first network address, and the second network having a second network address that is different from the first network address.
• wherein the image processing device includes a first processor, in communication with a first memory, executing a first process including:
• responding to a connection confirmation transmitted from the communication device;
• and
• communicating with the information processing device,
• wherein information processing device includes a second processor, in communication with a second memory, executing a second process including:
• responding to a connection confirmation transmitted from the communication device;
• and
• communicating with the image processing device, and
• wherein the communication device includes a first communication port for physically connecting with the image processing device on the first network through a first local area network cable, a second communication port for physically connecting with the information processing device on the second network through a second local area network cable, and a third processor, in communication with a third memory, executing a third process including:
• storing, within the communication device, connection confirmation information including identification information of the image processing device for permitting the image processing device to connect via the first communication port and identification information of the information processing device for permitting the information processing device to connect via the second communication port;
• and
• preempting a relay between the first network via the first communication port and the second network via the second communication port upon detecting that the identification information of the image processing device is not received from the first communication port and that the identification information of the information processing device is not received from the second communication port based on the connection confirmation information.