JP2003198624A - Method and apparatus for testing continuity between devices - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for testing a continuity between devices for searching a port number in which a communication is allowed/interrupted by a firewall unit. <P>SOLUTION: A testing communication apparatus 10 transmits a transmission request of a testing port number list by using a specific port number for a communication apparatus 10, and a communication apparatus 18 transmits a testing port number list prepared in advance to the apparatus 10. The apparatus 10 selects the testing port number for testing from the received testing port number list, and transmits a transmission request of the testing packet using the testing port number to the apparatus 18. The apparatus 18 transmits the request testing packet to the apparatus 10. The apparatus 10 judges that the communication is allowed by the firewall unit 14 by the testing port number when the apparatus 10 receives the testing packet transmitted from the apparatus 18. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an IP (Internet Pro
inter-device continuity test method for testing continuity between communication devices in a network communication system using a tocol), and in particular, the continuity between communication devices connected to an internal local area network protected by firewall technology and an external network, respectively. The present invention relates to a method for testing continuity between devices and a device therefor.

[0002]

2. Description of the Related Art In a network communication system, a device called a firewall device has conventionally been installed on the network for the purpose of improving the security of the network. This firewall device has a function called port filtering, and has TPC / UDP (Transmission
It permits or blocks communication according to the port number used for communication by Control Protocol / User Datagram Protocol). For example, the firewall device 34 in the communication system of FIG. 6 protects the internal local area network 36 such as an intranet from the external network 32, and the communication device 30 and the internal local area network connected to the external network 32.
When communication is performed with the communication device 38 connected to the 36, permission / blocking of the communication depends on permission / blocking by the communication port number in the firewall device 34. Permitting / blocking communication by the firefall device 34 is generally set and operated by an administrator who has authority to manage this device. Therefore, only the administrator of the firewall device 34 can set the permission / block for the communication between the communication device 30 and the communication device 38 via the firewall device 34, and can refer to the setting.

[0003]

However, even a person who does not have the management authority of the firewall device may want to refer to the setting of permission / blocking of communication by the firewall device. For example, a maintenance person who is in charge of maintaining the communication device 30 and the communication device 38 in FIG. 6 may want to know the communication permission / interruption setting in the firewall device 34 for a specific port number when performing device maintenance. .
Conventionally, in such a case, the maintenance person has to use a firewall device.
There was the annoyance of having to ask 34 administrators to investigate the setting of communication permission / blocking.

The present invention solves the problems of the prior art as described above. It is possible to obtain the port number for which communication is allowed / blocked by the firewall device without inquiring the administrator of the firewall device. The purpose is to provide a test method.

[0005]

In order to solve the above-mentioned problems, the present invention includes a first communication network and a second communication network connected via a firewall device having a port filtering function, and an IP A method for testing continuity between devices in a communication system in which communication is performed according to the method described in the test port number list from the test communication device connected to the first communication network to the communication device connected to the second communication network. The process of transmitting a transmission request using a specific port number, and the communication device receives the transmission request for the list of test port numbers, and the communication device for testing prepares the test port number that is provided in advance. The process of transmitting the list using a specific port number, and the test communication device receiving the test packet list From the device to the communication device, sending a test packet transmission request using the test port number selected from the list of test port numbers using a specific port number, and the test packet by the communication device. Receiving a transmission request from the communication device and transmitting the requested test packet from the communication device to the test communication device, and a test packet transmitted from the communication device by the test communication device when the test packet is received. The test port number of the test packet is characterized by determining that communication is permitted by the firewall device.

Further, the present invention is an apparatus comprising a test communication apparatus and a communication apparatus, which are respectively connected to a first communication network and a second communication network connected via a firewall apparatus having a port filtering function. Is a continuity test device, and the test communication device is TCP /
A first packet transmitting / receiving means for transmitting / receiving a packet using a specific port number according to IP or UDP / IP, and TCP /
A first information transmission / reception means for transmitting / receiving information according to a protocol belonging to the upper layer of IP or UDP / IP, and a list of test port numbers to the communication device via the first packet transmission / reception means and the first information transmission / reception means. When a transmission request is transmitted and a test port number list is received from the communication device, a test packet transmission request using the test port number selected from the received test port number list is transmitted to the communication device, When the first packet transmitting / receiving unit receives the test packet transmitted from the communication device, the test port number used for the test packet includes a control unit that determines that communication is permitted by the firewall device. The communication device has a second packet transmitting / receiving means for transmitting / receiving a packet using a specific port number according to TCP / IP or UDP / IP, and TCP / IP or Via the second information transmitting / receiving means for transmitting / receiving information according to the protocol belonging to the upper layer of UDP / IP, the memory storing the list of test port numbers, the second packet transmitting / receiving means and the second information transmitting / receiving means. , When a request to send a list of test port numbers is received from the test communication device, the test port number is read from the memory and sent to the test communication device, and a request to send a test packet is received from the test communication device. In this case, the second packet transmission / reception unit includes continuity test control means for instructing the transmission of the test packet.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the inter-device continuity test method according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of a communication system to which the inter-device continuity test method according to the present invention is applied. The inter-device continuity test method in this embodiment requests a communication device connected via a firewall device from a test communication device to send a test packet, and the communication device performs a test specified by the test communication device. The test packet using the test port number is transmitted to the test communication device, and the test communication device determines whether or not the test packet can be received.
This is to check whether communication by the test port number is permitted by the firewall device.

The communication system shown in FIG. 1 is an example of a network communication system for performing communication using IP, and includes an external network 12 and an internal local area network (LAN).
16) and a firewall device 14 inserted between the networks 12 and 16. The firewall device 14 has an internal LA due to the port filtering function.
This is a device that protects N 16 from the external network 12, and permits / blocks communication according to the port number used in the packet. The test communication device 10 is connected to the external network 12, and the communication device 18 is connected to the internal LAN 16.

The test communication device 10 and the communication device 18 are inter-device continuity test devices for investigating the port numbers for which communication is permitted and blocked by the fire fall device 14. FIG. 2 is a block diagram showing an embodiment of the test communication device 10. This test communication device 10 includes a control unit 104 and a control unit 10
4, input device 100, output device 102, client unit 106, and protocol stack unit 10
8 and a reception waiting timer 112, and a network controller 110 connected to the protocol stack unit 108. The protocol stack unit 108 is also connected to the client unit 106.

The input device 100 is composed of a keyboard and the like, and has information necessary for executing an inter-device continuity test, such as the IP address of the communication device 18, a connection start instruction, a request for transmitting a list of test port numbers, and a test port. The number, waiting time, test packet transmission request, connection end instruction, and the like are input and output to the control unit 104. Output device 10
2 consists of a display etc., and input device 10
The information input to 0 and the information output from the control unit 104, such as a list of test port numbers and test results, are displayed.

The control unit 104 controls the client unit 106, the reception waiting timer 112 and the like to execute an inter-device continuity test. Specifically, when a connection start instruction and a connection end instruction are input to the input device 100, the client unit 106 is instructed to start and end the connection with the partner server, and the waiting time is input from the input device 100. At this time, the waiting time is output to the reception waiting timer 112 to instruct the setting of the waiting time. In addition, the IP address of the communication device 18 input from the input device 100 is output to the protocol stack unit 108, and the request to send the list of test port numbers, the test port number, and the request to send the test packet are output to the client unit 106. Then, the list of test port numbers output from the client unit 106 is output to the output device 102.

The control unit 104 further includes a client unit 10
After outputting a test packet transmission request to 6, the reception waiting timer 112 is instructed to start activation. Then, when the reception notification for notifying the reception of the test packet is received from the protocol stack unit 108 before the waiting time elapses, it is determined that the communication by the test port number is permitted by the firewall device 14, and the reception waiting timer is set. When the elapse of the waiting time is notified from 112, it is determined that communication by the test port number is blocked by the firewall device 14, and the determination result is output to the output device 102. When the control unit 104 receives the reception notification from the protocol stack unit 108, the control unit 104 instructs the reception waiting timer 112 to stop the operation.

The client unit 106 is an information transmitting / receiving unit that transmits / receives information according to the Telnet protocol, which is an upper layer of TCP / UDP, and is a Telnet client that requests a predetermined service from the server 202 of the communication device 18. Specifically, when a connection start instruction is given from the control unit 104, a connection is requested to the server 202, and after the connection is established,
Send a request to send a list of test port numbers and a request to send a test packet from the control unit 104 to the server 202,
The test port number list transmitted from 202 is received and output to the control unit 104, and when a connection termination instruction is given from the control unit 104, the connection with the server 202 is terminated.

The port number used for communication between the client unit 106 and the server 202 is notified in advance from the firewall device 14 to the test communication device 10 and the communication device 18. In addition, in the present embodiment, the client unit 106 uses Te to communicate with the server 202 of the communication device 18.
Although the lnet protocol is used, the protocol is not limited to the Telnet protocol as long as it is a protocol that allows text-based data transmission / reception, and another protocol such as HTTP (Hyper Text Transfer Protocol) may be used.

The protocol stack unit 108 is a packet transmitting / receiving unit that transmits / receives packets according to TCP / IP or UDP / IP. Specifically, using the IP address of the communication device 18 given from the control unit 104, the port number given in advance, etc., the IP header and TCP / UD addressed to the communication device 18 are used.
A P header is generated, information output from the client unit 106, for example, a transmission request for a list of test port numbers is added to the P header to generate a packet, which is output to the network controller 110. Also, the network controller 11
A packet addressed to the test communication device 10 is selected from the packets received by 0, and information included in the packet, for example, a list of test port numbers is extracted and the client unit is selected.
Output to 106.

Further, when the protocol stack unit 108 receives the test packet transmitted from the communication device 18,
A reception notification for notifying that the test packet has been received is output to the control unit 104. Network controller 110
Is, for example, an interface unit that interfaces with a network connected to the external network 12,
It outputs the packet from the protocol stack unit 108 to the network, receives the packet from the network, and outputs it to the protocol stack unit 108.

The reception waiting timer 112 is a timer that outputs a waiting time elapse notification when a set waiting time has elapsed, and has a counter that decrements the count value by 1 in accordance with a predetermined clock. This counter sets this as an initial value when a waiting time is given from the control unit 104, starts counting when a start start instruction is given, and generates a waiting time elapsed notification when the count value becomes 0. . However,
When the control unit 104 gives an instruction to stop the operation, the counting is stopped. Alternatively, the count value of the counter of the reception waiting timer 112 may be incremented by one in accordance with the clock, and the control unit 104 may compare the count value of the counter with the waiting time to detect the elapse of the waiting time.

On the other hand, the communication device 18 connected to the internal LAN 16
Is a communication device including a function of transmitting a list of test port numbers and a test packet in response to a request from the test communication device 10. The test device is combined with the test communication device 10 to execute an inter-device continuity test. FIG. 3 is a block diagram showing an embodiment of the communication device 18. The communication device 18 includes a continuity test control unit 200, a server unit 202 connected to the continuity test control unit 200, and a memory 20.
8, a continuity test control unit 200 and a protocol stack unit 204 connected to the server unit 202, and a network controller 206 connected to the protocol stack unit 204. Note that parts that are not related to the inter-device continuity test are omitted.

The continuity test control unit 200 includes the test communication device 10
The inter-device continuity test is executed in response to a request from the customer. Specifically, when the server unit 202 receives a test port number list transmission request, it reads the test port number list from the memory 208 and outputs it to the server unit 202, and the server unit 202 sends a test packet transmission request. When received, it instructs the protocol stack unit 204 to transmit the test packet. When instructing to send the test packet,
Connection request from the test packet transmission request from the server unit 202
The IP address (IP address of the test communication device 10), the protocol type (TCP or UDP) and the test port number are extracted and notified to the protocol stack unit 204.

The server unit 202 is in the upper layer of TCP / UDP.
An information transmitting / receiving unit that transmits / receives information according to the Telnet protocol, and is a Telnet server that provides a service in response to a request from the client unit 106 of the test communication device 10. Specifically, a connection is established in response to a connection request from the client unit 106, and a request to send a list of test port numbers and a request to send a test packet from the client unit 106 are received and output to the continuity test control unit 200. Then, the list of test port numbers from the continuity test control unit 200 is transmitted to the client unit 106, and the connection is terminated in response to the connection termination request from the client unit 106.

The protocol stack unit 204 is a packet transmitting / receiving unit that transmits / receives packets to / from the protocol stack 108 of the test communication device 10 according to TCP / IP or UDP / IP. Specifically, the network controller
A packet addressed to the communication device 18 is selected from the packets received by 206, and information contained in the packet, for example, a transmission request of a list of test port numbers is extracted and the server unit 20 is selected.
Output to 2. The protocol stack unit 204 also generates an IP header and a TCP / UDP header addressed to the test communication device 10, adds a list of test port numbers given from the server unit 202 to generate a packet, and sends the packet to the network controller 206. Output.

The protocol stack unit 204 further receives the test packet transmission instruction from the continuity test control unit 200, the IP address, the protocol type, and the test of the test communication device 10 notified from the continuity test control unit 200. A predetermined test packet is generated using the communication port number and output to the network controller 206. Information indicating that the packet is a test packet is added to the test packet. In the control unit 104 of the test communication device 10, when the client unit 106 receives this information, the protocol stack unit 108 uses the test packet. It may be determined that the packet has been received.

The network controller 206 is an interface section for interfacing with the network (internal LAN 16), outputs the packet from the protocol stack section 204 to the network, receives the packet from the network, and outputs it to the protocol stack section 204. To do.
The memory 208 connected to the continuity test control unit 200 is
All port numbers used by communication device 18 (for example,
This is a memory that stores in advance a list indicating 0 to 65535 as a list of test port numbers.

An inter-device continuity test using the test communication device 10 and the communication device 18 thus configured will be described with reference to the flowcharts of FIGS. 4 and 5. 4 is a flowchart when the test packet is permitted to pass by the firewall device 14, and FIG. 5 is a flowchart when the test packet is rejected to be passed by the firewall device 14. In the control unit 104 of the test communication device 10, the connection destination I
When the P address (IP address of the communication device 18) and the connection start instruction to the partner server are input, the protocol stack unit 108 is notified of the IP address of the communication device 18 that is the connection destination, and the client unit 106 is notified of the communication device. The connection start is instructed to 18 server units 202.

The client unit 106 receives a connection start instruction from the control unit 104 and receives the server unit 202 of the communication device 18.
Request a connection to and establish a connection. As described above, the port number used for communication between the client unit 106 and the server unit 202 is a number permitted by the firewall device 14, and the firewall device 14 side allows the test communication device 10 and the communication device 18 to operate. Have been notified in advance. Client part 106 and server part
The 202 transmits and receives commands such as transmission requests and data using this connection (command transmission / reception port). Figure 4
In FIG. 5 and FIG. 5, communication using this command transmission / reception port is indicated by a dotted line.

When a transmission request for the list of test port numbers is input to the input device 100, the control unit 104 outputs this transmission request to the client unit 106. Client part
At 106, the transmission request of the list of test port numbers from the control unit 104 is output to the protocol stack unit 108, and at the protocol stack unit 108, the predetermined TCP / UDP header and IP
A transmission request for the list of test port numbers from the client 1 unit 06 is added to the header to generate a packet, and the generated packet is transmitted to the communication device 18 via the network controller 110 (step S10 in FIG. 4).

The packet transmitted from the communication device 10 reaches the communication device 18 through the external network 12, the firewall device 14 and the internal LAN 16 shown in FIG. Communication device
The network controller 206 of 18 receives the packet transmitted from the test communication device 10, and the protocol stack unit 204 receives the packet from the network controller 206 and extracts the transmission request of the list of test port numbers. Output to the server unit 202. The server unit 202 outputs the transmission request for the list of test port numbers from the protocol stack unit 204 to the continuity test control unit 200.

Upon receipt of this transmission request, the continuity test control unit 200 reads the list of test port numbers from the memory 208 and outputs it to the server unit 202. The server unit 202 outputs the list of test port numbers from the continuity test control unit 200 to the protocol stack unit 204, and the protocol stack unit 204
In the specified TCP / UDP header and IP header,
A packet is generated by adding the list of test port numbers from 202, and the generated packet is added to the network controller.
It is transmitted to the test communication device 10 via 206 (step S3
0).

The packet transmitted from the communication device 18 reaches the test communication device 10 through the internal LAN 16, the firewall device 14 and the external network 12 of FIG. In the network controller 110 of the test communication device 10,
The packet transmitted from the communication device 18 is received, and the protocol stack unit 108 receives the packet from the network controller 110.
It receives a packet from the test port number list, and outputs it to the client unit 106. The client unit 106 outputs the list of test port numbers received from the protocol stack unit 108 to the control unit 104, and the control unit 104
Then, this list of test port numbers is output to the output device 102 and displayed on the display.

The operator of the test communication device 10 selects a port number (test port number) for performing the inter-device continuity test from the list of test port numbers displayed on the display, and then the test port number and connection are made. The above-mentioned IP address (in this embodiment, the IP address of the test communication device 10), the protocol type, and the test packet transmission request are input to the input device 100.
(Step S12), and then the waiting time is input to the input device 100. When the waiting time is the same for all the test port numbers and is fixed, if the waiting time is stored in the control unit 104 in advance, it is not necessary to input it for each test port number. .

The control unit 104 receives the waiting time from the input device 100, outputs it to the reception waiting timer 112 to instruct the setting, and the reception waiting timer 112 sets the waiting time in the counter as an initial value ( Step S14
). The waiting time is set to the time required for the test packet to pass through the firewall device 14 and reach the test communication device 10 after the reception waiting timer 112 is activated. Next, the control unit 104 receives a test packet transmission request from the input device 100, generates a test packet transmission request including the test port number, the IP address of the connection destination, and the protocol type, and outputs it to the client unit 106. .

The client unit 106 sends the test packet transmission request received from the control unit 104 to the protocol stack unit.
To the protocol stack unit 108,
A test packet transmission request from the client unit 106 is added to the TCP / UDP header and IP header to generate a packet, and the generated packet is sent to the network controller 110.
To the communication device 18 via (step S16). After outputting the test packet transmission request to the client unit 106, the control unit 104 instructs the reception waiting timer 112 to start activation. The counter of the reception waiting timer 112 is
The counting is started (step S18), and the initial value (waiting time) is decremented by 1 every predetermined clock. Then, when the count value becomes 0, a waiting time elapse notification for notifying the elapse of the waiting time is output to the control unit 104.

The packet transmitted from the test communication device 10 reaches the communication device 18 through the external network 12, the firewall device 14 and the internal LAN 16. Communication device
The network controller 206 of 18 receives the packet transmitted from the test communication device 10, and the protocol stack unit 204 receives the packet from the network controller 206 and extracts the test packet transmission request. Output to. The server unit 202 outputs the test packet transmission request received from the protocol stack unit 204 to the continuity test control unit 200.

The continuity test control unit 200 extracts the test port number, the IP address and the protocol type of the connection destination from the test packet transmission request from the server unit 202, outputs them to the protocol stack unit 204, and transmits the test packet. Instruct. In the protocol stack section 204,
A predetermined test packet is generated using the test port number, the IP address of the connection destination, and the protocol type received from the continuity test control unit 200, and the generated test packet is transmitted via the network controller 206 to the test communication device. Send to 10 (step S32). In FIGS. 4 and 5, communication using the test port is indicated by a chain line.

The test packet transmitted from the communication device 18 is sent to the firewall device 14 via the internal LAN 16 shown in FIG.
Entered in. The firewall device 14 performs port filing on the input test packet, allows the test packet to pass when communication by the test port number is permitted, and blocks it when not permitted. The test packet that has passed through the firewall device 14 is transmitted through the external network 12 to the test communication device.
To reach 10.

The network controller 110 of the test communication device 10 receives the packet transmitted from the communication device 18 and outputs it to the protocol stack unit 108. In the protocol stack unit 108, the network controller 110
When the test packet is received from, the control unit 104 outputs a reception notification notifying the reception of the test packet. Control unit 10
In 4, when receiving the reception notification from the protocol stack unit 108 before receiving the waiting time notification from the reception waiting timer 112, the reception waiting timer 112 is instructed to stop the operation (step S20), and the test port number is set. It is determined that the communication is permitted by the firewall device 14 (step S22).

However, if the test packet is not permitted to pass by the firewall device 14, the protocol stack unit 108 cannot receive the test packet even after the waiting time elapses. Waiting timer 112
Outputs a wait time elapsed notification when the wait time has elapsed (step S24 in FIG. 5). When the waiting time elapse notification is received from the reception waiting timer 112, the control unit 104 determines that communication with the test port number is not permitted by the firewall device 14 (step S26). The control unit 104 outputs the determination result to the output device 102 and displays it on the display.

By executing the above-mentioned inter-device continuity test for each port number in the test port number list, the operator can communicate with the firewall device 14 for all port numbers in the test port number list. You can know if you are authorized or not.

In this embodiment, the test communication device 10 is connected to the external network 12 and the communication device 18 is connected to the internal LAN 16 to check whether or not the packet is transmitted from the internal LAN 16 to the external network 12. However, by connecting the test communication device 10 to the internal LAN 16 and the communication device 18 to the external network 12, it is possible to check whether or not a packet is transmitted from the external network 12 to the internal LAN 16 direction. become.

[0040]

According to the inter-device continuity test method of the present invention, a test port number is designated from a test communication device to a communication device connected through a firewall device, and a test packet is transmitted. Since it is possible to know the port number at which communication is permitted / blocked in the firewall device by requesting transmission and whether the test communication device can receive the test packet, the connection to the administrator of the firewall device can be established. It is possible to know the port number that the firewall device permits communication without checking the permitted port number.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a communication system to which an inter-device continuity test method according to the present invention is applied.

2 is a block diagram showing an embodiment of a test communication device 10 in the communication system shown in FIG.

3 is a block diagram showing an embodiment of a communication device 18 in the communication system shown in FIG.

FIG. 4 is a flowchart showing operations of the test communication device 10 and the communication device 18 shown in FIG. 1 when the test packet can pass through the firewall device.

5 is a flowchart showing the operation of the test communication device 10 and the communication device 18 shown in FIG. 1 when the test packet cannot pass through the firewall device.

FIG. 6 is an explanatory diagram for explaining a conventional connection method between communication devices.

[Explanation of symbols]

10 Test communication device 12 External network 14 Firewall device 16 Internal Local Area Network 18 Communication equipment

Claims (2)

[Claims] 1. An IP (Intern) including a first communication network and a second communication network connected via a firewall device having a port filtering function.
et Protocol), a method for testing continuity between devices in a communication system, the method comprising: communication from a test communication device connected to the first communication network to a communication connected to the second communication network. A step of transmitting a request for transmitting a list of test port numbers to a device using a specific port number; and a request for transmitting the list of test port numbers is received by the communication device, and the test is performed from the communication device. Transmitting a list of test port numbers provided in advance to the communication device for test using the specific port number, and receiving the list of test packets by the test communication device, From the device to the communication device, a request for transmitting a test packet using the test port number selected from the test port number list is sent to the specific device. A step of transmitting the requested test packet from the communication device to the test communication device by receiving a test packet transmission request by the communication device. And when the test communication device receives the test packet transmitted from the communication device, the test port number of the test packet determines that communication is permitted by the firewall device. Test method for continuity between devices. 2. An inter-apparatus continuity test device comprising a test communication device and a communication device respectively connected to a first communication network and a second communication network connected via a firewall device having a port filtering function. The test communication device is a TCP / IP (Transmission Control)
Protocol / IP) or UDP / IP (User Datagram Protocol)
/ IP), a first packet transmitting / receiving means for transmitting / receiving a packet using a specific port number, and a first information transmitting / receiving means for transmitting / receiving information according to a protocol belonging to an upper layer of TCP / IP or UDP / IP, A request for transmitting a list of test port numbers is transmitted to the communication device via the first packet transmitter / receiver and the first information transmitter / receiver, and is received when the list of test port numbers is received from the communication device. A request for transmitting a test packet using a test port number selected from a list of test port numbers is transmitted to the communication device, and the first packet transmitting / receiving means receives the test packet transmitted from the communication device. When this occurs, the test port number used for the test packet and the control means for determining that the firewall device permits communication. The communication device includes a second packet transmitting / receiving unit that transmits / receives a packet according to TCP / IP or UDP / IP using the specific port number, and the protocol belonging to an upper layer of TCP / IP or UDP / IP. A second information transmitting / receiving means for transmitting / receiving information according to the above, a memory for storing a list of test port numbers, and a test communication device for testing via the second packet transmitting / receiving means and the second information transmitting / receiving means. When a request for transmitting a list of port numbers is received, the test port numbers are read from the memory and transmitted to the test communication device,
An inter-device continuity test device comprising: a continuity test control means for instructing the second packet transmission / reception unit to transmit the test packet when a test packet transmission request is received from the test communication device. .