Communication device, communication method, and communication system

Abstract

A communication device is connected to first and second networks. The communication device includes a processor executing a process including relaying communication between the first and second networks; and confirming connection to a first device connected to the first network or a second device connected to the second network, based on a device list registered in advance. The confirming includes blocking the relaying when the confirmation of the connection to the first device is unsuccessful; enabling the relaying when the confirmation of the connection to the first device is successful and when the second device is not registered in the device list; enabling the relaying when the confirmation of the connections to the first and second devices is successful; and blocking the relaying when the confirmation of the connection to the first device is successful and when the confirmation of the connection to the second device is unsuccessful.

What is claimed is: 
     
         1 . A communication device connected to a first network and a second network, the communication device comprising a processor, in communication with a memory, executing a process including:
 relaying communication between the first network and the second network via a network interface included in the communication device; and   confirming connection to a first device connected to the first network or a second device connected to the second network, based on a device list stored in advance in a storage device included in the communication device, the connection to the first device or the second device being made via a port included in the communication device, wherein   the confirming includes:
 blocking the relaying upon determining that the confirmation of the connection to the first device connected to the first network is unsuccessful based on the device list; 
 enabling the relaying upon determining that the confirmation of the connection to the first device connected to the first network is successful based on the device list and upon determining that the second device connected to the second network is not registered in the device list; 
 enabling the relaying upon determining that the confirmation of the connection to the first device connected to the first network is successful based on the device list and upon determining that the confirmation of the connection to the second device connected to the second network is successful based on the device list; and 
 blocking the relaying upon determining that the confirmation of the connection to the first device connected to the first network is successful based on the device list and upon determining that the confirmation of the connection to the second device connected to the second network is unsuccessful based on the device list. 
   
     
     
         2 . The communication device according to  claim 1 , wherein
 a logical address, associated with each of the first device and the second device, is registered in the device list, and   the confirming includes confirming the connection to the first device or the second device according to an echo response for which a transmission destination is identified by the logical address.   
     
     
         3 . The communication device according to  claim 1 , wherein
 a logical address and a physical address, associated with each of the first device and the second device, are registered in the device list, and   the confirming includes confirming the connection to the first device or the second device by acquiring, from the first device or the second device for which the confirmation is being made, the physical address based on the logical address, and matching the acquired physical address to the physical address registered in the device list.   
     
     
         4 . The communication device according to  claim 3 , wherein
 a part of the physical address, associated with each of the first device and the second device, is specified in advance, and   the confirming includes confirming the connection to the first device or the second device by matching a part of the acquired physical address to the part of the physical address specified in advance.   
     
     
         5 . The communication device according to  claim 1 , wherein
 an identifier, which is on a network management protocol associated with each of the first device and the second device, is specified in advance, and   the confirming includes confirming the connection to the first device or the second device by acquiring an identifier included in a response according to the network management protocol, and matching the acquired identifier to the identifier specified in advance.   
     
     
         6 . The communication device according to  claim 1 , wherein the processor executes the process further including:
 displaying, on a display, a state of the relaying being enabled or a state of the relaying being blocked.   
     
     
         7 . The communication device according to  claim 1 , wherein the confirming includes confirming again the connection to the first device connected to the first network and the connection to the second device connected to the second network, upon determining that a predetermined time has elapsed from a time point when the relaying has been enabled or blocked. 
     
     
         8 . A communication method executed by a computer included in communication device connected to a first network and a second network, the communication method comprising:
 relaying communication between the first network and the second network via a network interface included in the communication device; and   confirming connection to a first device connected to the first network or a second device connected to the second network, based on a device list stored in advance in a storage device included in the communication device, the connection to the first device or the second device being made via a port included in the communication device, wherein   the confirming includes:
 blocking the relaying upon determining that the confirmation of the connection to the first device connected to the first network is unsuccessful based on the device list; 
 enabling the relaying upon determining that the confirmation of the connection to the first device connected to the first network is successful based on the device list and upon determining that the second device connected to the second network is not registered in the device list; 
 enabling the relaying upon determining that the confirmation of the connection to the first device connected to the first network is successful based on the device list and upon determining that the confirmation of the connection to the second device connected to the second network is successful based on the device list; and 
 blocking the relaying upon determining that the confirmation of the connection to the first device connected to the first network is successful based on the device list and upon determining that the confirmation of the connection to the second device connected to the second network is unsuccessful based on the device list. 
   
     
     
         9 . The communication method according to  claim 8 , wherein
 a logical address, associated with each of the first device and the second device, is registered in the device list, and   the confirming includes confirming the connection to the first device or the second device according to an echo response for which a transmission destination is identified by the logical address.   
     
     
         10 . The communication method according to  claim 8 , wherein
 a logical address and a physical address, associated with each of the first device and the second device, are registered in the device list, and   the confirming includes confirming the connection to the first device or the second device by acquiring, from the first device or the second device for which the confirmation is being made, the physical address based on the logical address, and matching the acquired physical address to the physical address registered in the device list.   
     
     
         11 . The communication method according to  claim 10 , wherein
 a part of the physical address, associated with each of the first device and the second device, is specified in advance, and   the confirming includes confirming the connection to the first device or the second device by matching a part of the acquired physical address to the part of the physical address specified in advance.   
     
     
         12 . The communication method according to  claim 8 , wherein
 an identifier, which is on a network management protocol associated with each of the first device and the second device, is specified in advance, and   the confirming includes confirming the connection to the first device or the second device by acquiring an identifier included in a response according to the network management protocol, and matching the acquired identifier to the identifier specified in advance.   
     
     
         13 . The communication device according to  claim 8 , further comprising:
 displaying, on a display, a state of the relaying being enabled or a state of the relaying being blocked.   
     
     
         14 . The communication method according to  claim 8 , wherein the confirming includes confirming again the connection to the first device connected to the first network and the connection to the second device connected to the second network, upon determining that a predetermined time has elapsed from a time point when the relaying has been enabled or blocked. 
     
     
         15 . 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,   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 third processor, in communication with a third memory, executing a third process including:   relaying communication between the image processing device and the information processing device via a network interface included in the communication device; and   confirming connection to the image processing device or the information processing device, based on a device list stored in advance in a storage device included in the communication device, the connection to the image processing device or the information processing device being made via a port included in the communication device, wherein   the confirming includes:
 blocking the relaying upon determining that the confirmation of the connection to the image processing device is unsuccessful based on the device list; 
 enabling the relaying upon determining that the confirmation of the connection to the image processing device is successful based on the device list and upon determining that the information processing device is not registered in the device list; 
 enabling the relaying upon determining that the confirmation of the connection to the image processing device is successful based on the device list and upon determining that the confirmation of the connection to the information processing device is successful based on the device list; and 
 blocking the relaying upon determining that the confirmation of the connection to the image processing device is successful based on the device list and upon determining that the confirmation of the connection to the information processing device is unsuccessful based on the device list.