Remote management system, router, and remote management method

Abstract

A remote management system and method for establishing a communication session with a network device with low security risk and performing remote management are provided. [Solution] A remote management system 100 comprising a network device 20 connected to a private network 10, a router 30, and a remote management server 50 and operation terminal 60 connected to the Internet 40, wherein the network device randomly generates a UDP port number and an authentication key and transmits them to the remote management server in advance, and when the operation terminal requests the remote management server to operate the network device, the remote management server transmits the authentication key to the network device, and if the received authentication key matches the authentication key transmitted in advance, the network device establishes a communication session between the network device and the remote management server, and the operation terminal remotely manages the network device.

Description

[Technical Field]

[0001] The present invention relates to a remote management system and a remote management method for remotely managing network devices connected to a private network from the Internet. [Background technology]

[0002] With regard to the remote management of network devices and the initiation of communications required for remote management, the following inventions, for example, have been disclosed.

[0003] Patent document 1 (JP 2023-61252 A) discloses an information processing system, information processing equipment, management server, and program that enable log collection and investigation through remote maintenance operations of equipment when a request for support for the equipment is made. In the information processing system described in Patent Document 1, the target device establishes a communication session with a management server, receives a request from the management server that established the communication session, responds to the request, and sends predetermined information. A disconnection processing unit of the management server or the target device discards the established communication session when a predetermined termination condition is satisfied.

[0004] Furthermore, Patent Document 2 (Japanese Patent Laid-Open Publication No. 2023-52288) discloses a relay method that enables secure access to a target terminal for remote management. In the relay method described in Patent Document 2, a connection management device in a relay system, upon receiving terminal identification information identifying a target terminal from a client terminal, identifies a first relay device that will relay the communication and identifies connection information for the client terminal to connect to the first relay device. The connection management device associates the identified connection information with the terminal identification information and stores them in a storage unit, and notifies the client terminal of the identified connection information. Upon receiving access from the client terminal based on the connection information, the identified first relay device relays communication between the client terminal and the target terminal based on the terminal identification information associated with the connection information.

[0005] Furthermore, Patent Document 3 (JP 2020-160984 A) discloses a data collection device, typified by an IoT device, that reduces security risks without impairing user convenience. The data collection side device described in Patent Document 3 includes a command receiving unit that receives a port open command specifying a port from the data using side device via a wireless communication network, an authentication processing unit that executes authentication processing for the data using side device that sent the port open command, a command execution unit that executes the port open command to open the port if authentication of the data using side device is successful, and a data communication unit that performs data communication using the port in response to a request from the data using side device.

[0006] Furthermore, Patent Document 4 (International Publication No. 2016 / 207927) discloses a network connection technology for remotely controlling a device in a remote location via a network. The remote maintenance system of Patent Document 4 includes a maintenance management device connected to a user device and a communication relay device connected to a remotely controlled device. The maintenance management device transmits message data addressed to the communication relay device, which is unique identification information of a mobile communication network that has been assigned to the communication relay device in advance. In connection with receiving the message data, the communication relay device notifies the maintenance management device of an IP address that is dynamically assigned to itself. The maintenance management device transmits information related to remote operation received from the user device to the communication relay device, with the notified IP address as the destination, and the communication relay device relays the information related to remote operation received from the maintenance management device to the remotely controlled device.

[0007] Patent document 5 (JP Patent Publication No. 2013-201621) describes a port opening / closing control system that enables remote access to a port of a home gateway device from a user terminal using normal Internet usage procedures, while avoiding unnecessarily opening the port to the Internet. In the port opening / closing control system described in Patent Document 5, a residential gateway device closes a port to the Internet. The command device has a DNS content server unit, and when a user terminal executes the normal Internet usage procedure of specifying the host name of a gateway device, the terminal sends a name resolution request. Upon receiving this name resolution request, the command device replies with a DNS response specifying TTL = 0 seconds, and also refers to a management table of the gateway device's host name and closed network address to send a port open request to the gateway device via the closed network. The terminal accesses the gateway device's port using the global IP address acquired in the DNS response, and when this access ends, the gateway device closes the port.

[0008] Furthermore, Patent Document 6 (JP 2013-206260 A) discloses an authentication method that allows communication required for remote management to be started in response to an external request, with a lower security risk. The authentication method described in Patent Document 6 involves recording a predetermined authentication format in a relay device, and the external request terminal dividing authentication data that conforms to the authentication format into sizes that can be embedded as port numbers in packets such as TCP or UDP, embedding the data in the port number portion of a series of packets and sending them in succession in order to the device, and the device with communication capabilities monitoring the sequential pattern of port numbers in packets received by the firewall, referring to the recorded authentication format, and if it detects that the pattern conforms to the authentication format, opening a port in the firewall for access to accept access, or launching specified software to accept the access. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2023-61252 [Patent Document 2] Japanese Patent Application Publication No. 2023-52288 [Patent Document 3] Japanese Patent Application Publication No. 2020-160984 [Patent Document 4] International Publication No. 2016 / 207927 [Patent Document 5] Japanese Patent Application Laid-Open No. 2013-201621 [Patent Document 6] Japanese Patent Application Laid-Open No. 2013-206260 Summary of the Invention [Problem to be solved by the invention]

[0010] In order to avoid security risks from the outside, network devices connected to a private network are usually configured so that they can connect to servers on the Internet, but cannot connect to the network devices from servers on the Internet. However, when a support department remotely manages a network device connected to a private network, it is necessary to connect to the network device from a server on the Internet, etc. Many patent documents have been disclosed regarding methods for connecting from a server on the Internet to a network device connected to a private network.

[0011] In the information processing system described in Patent Document 1, when a support representative instructs a user to perform a specified support request operation on the operation unit of the target device (for example, by pressing and holding a certain button), the target device establishes a communication session with the management server, and thereafter the management server can communicate with the target device. This method poses little security risk because a communication session is not established unless the user performs a specific support request operation on the operation unit of the target device. However, forcing users who call the support desk to perform additional operations can be a significant burden for users who are unfamiliar with operating network devices.

[0012] Therefore, Patent Documents 2 to 6 describe methods for establishing a communication session between a network device and an external management server without requiring the user to perform a support request operation. In Patent Document 2, when a connection management device notifies a relay device of relay information including the port number of the target terminal associated with the relay device, the relay device establishes a connection between the relay device and the target terminal based on terminal identification information different from a private address and the port number used when the target terminal communicates. Although this method is relatively easy, port numbers are in the range of 0 to 65535, and there is a possibility that security may be breached if the port number is detected by a port scan or if the port numbers happen to match.

[0013] In contrast to this, in Patent Document 3, a port open command is sent from the data using device to the data collecting device via a wireless communication network, and if the data using device that sent the port open command is successfully authenticated, the port is released, thereby reducing the security risk faced by the data collecting device. In this case, however, the data using device needs a wireless communication network in addition to a normal connection to the Internet.

[0014] In the remote maintenance system of Patent Document 4, the maintenance management device also uses the SMS function of the mobile communication network to send a connection request message to a communication relay device that has been assigned unique identification information of the mobile communication network in advance. In Patent Document 4, the IP address that changes dynamically each time a connection request message is sent is received from the communication relay device, and information related to remote operation is relayed to the communication relay device based on the received IP address, thereby further reducing security risks. However, even in this case, the maintenance management device needs a wireless communication network in addition to a normal connection to the Internet.

[0015] In the port opening / closing control system of Patent Document 5, the home gateway device does not directly accept an opening request from a user terminal, but rather the command device stores the private network address of the home gateway device in association with the host name of the DNS registration request, and when it receives a name resolution request for the host name from the Internet, it opens a port that the home gateway device can use by sending a port opening request to the private network address of the home gateway device stored in association with the host name. In this case, in addition to the normal Internet, a closed network is also required between the command device and the home gateway device.

[0016] The authentication method of Patent Document 6 involves recording a predetermined authentication format in an external request terminal attempting to access from an external network and in a device with communication capabilities that has a firewall and accepts that access. The external request terminal divides the authentication data into sizes that can be embedded as port numbers in packets such as TCP or UDP, embeds the data in the port number portion of a series of packets, and sends them in order to the device. The device with communication capabilities then monitors the consecutive patterns of port numbers in the received packets to perform authentication. This method does not require a wireless communication network or a closed network, and since authentication is performed by monitoring the consecutive patterns of port numbers in received packets, it can reduce security risks compared to authentication using IP addresses or port numbers, such as in Patent Document 2. However, in this case, the authentication data embedded in the port number portion must be sent in succession in order, which may take some time for authentication to be completed. Also, on the Internet, the order in which the authentication data is received may differ from the order in which it is sent, which may prevent smooth authentication.

[0017] The main object of the present invention is to provide a remote management system and a remote management method that establishes a communication session with a network device that poses a low security risk and remotely manages the network device without requiring the user to perform any special support request operations. Another object of the present invention is to provide a remote management system and a remote management method that establish a communication session with low security risk without establishing a communication path between the network device and the system other than the Internet, and that remotely manages the network device. [Means for solving the problem]

[0018] (1) According to one aspect, a remote management system includes a network device connected to a private network, a router that relays between the private network and the Internet, and a remote management server and an operation terminal connected to the Internet, wherein the network device randomly generates a UDP port number and an authentication key for the network device and transmits them in advance to the remote management server via a secure path together with device-specific information for the network device, the remote management server receives the UDP port number, authentication key, and device-specific information for the network device, and stores the received UDP port number, authentication key, and device-specific information for the network device, and when the operation terminal requests the remote management server to perform an operation on the network device, the remote management server transmits the authentication key to a UDP port of the network device that corresponds to the device-specific information of the network device, and when the authentication key received at the UDP port matches the authentication key that was transmitted in advance, the network device establishes a communication session between the network device that corresponds to the device-specific information and the remote management server, and the operation terminal remotely manages the network device via the remote management server and the communication session.

[0019] Typically, a router that relays between a private network and the Internet allows communication from the private network side to the Internet, but does not allow communication from the Internet side to the private network, except in the case of a reply to communication from the private network side to the Internet. Therefore, when establishing a secure communication session using TLS or the like between a network device and a remote management server, it is necessary to establish a communication session from the network device to the remote management server. This requires the user of the network device to perform some kind of operation. However, many network device users are unfamiliar with operating network devices, and performing operations to establish a communication session can be a significant burden for them.

[0020] In this case, to avoid burdening users, it is possible to allow communication from the Internet to the private network by sharing the source and / or destination IP addresses and port numbers. However, port numbers run the risk of being detected by methods such as port scanning, and this is not a sufficient measure to reduce security risks. On the other hand, it is also possible to send instructions to allow communication from the Internet to the private network via a wireless communication network or a closed network rather than via the regular Internet. However, in this case, it is necessary to provide a wireless communication network or a closed network between the remote management server and the network device, which increases costs.

[0021] In a remote management system according to one aspect, a network device randomly generates a UDP port number and an authentication key for the network device and shares them in advance with a remote management server via a secure path along with device-specific information for the network device. When it becomes necessary to establish a communication session, the remote management server transmits the authentication key to the UDP port of the network device that has been shared in advance, and the network device authenticates the authentication key, thereby transmitting a request to establish a communication session from the remote management server on the Internet to the network device, and the network device establishes a communication session between the network device and the remote management server. In this case, not only must the port numbers match but the authentication keys must also match, which reduces the risk of establishing an incorrect communication session due to a cyber attack, etc. It is desirable that the authentication key be composed of binary data of, for example, 256 bits or more.

[0022] (2) A remote management system according to a second aspect of the present invention may be configured such that when a UDP packet is sent from the Internet side to a UDP port of a network device, the network device does not make any response or transmission.

[0023] When a UDP packet is sent to a UDP port shared with a remote management server, if a network device responds or sends something, the port scan will reveal to the port scanner that the port is in listening mode, which could lead to unauthorized intrusion using a so-called DoS attack. In the remote management system according to the second aspect of the present invention, even when a network device is subjected to a port scan, it does not respond or transmit any data so that the corresponding port is not detected as being in a standby state.

[0024] (3) A remote management system according to a third aspect of the present invention is the remote management system according to the first aspect to the second aspect of the present invention, wherein the network device is a wireless LAN access point or a NAS.

[0025] In this case, the remote management system can remotely manage the wireless LAN access point or NAS. Note that the network device may also be a network camera, a network game console, or the like.

[0026] (4) A remote management system according to a fourth aspect of the present invention is the remote management system according to the first aspect to the second aspect of the present invention, wherein the network device may include a function of a router.

[0027] The network device may be, for example, a wireless LAN router that includes the functionality of a router, or a router itself. In this case, the remote management system can remotely manage the router.

[0028] (5) A remote management system according to a fifth aspect of the present invention is the remote management system according to the first aspect to the fourth aspect of the present invention, wherein TLS (Transport Layer Security) is used for the secure path and the communication session.

[0029] TLS is a widely adopted security protocol used, for example, for communication between network devices and the AWS cloud (AWS IoT Core). TLS enables secure two-way communication between network devices and remote management servers.

[0030] (6) The remote management system according to the sixth aspect of the present invention is a remote management system according to the fifth aspect of the present invention, wherein the remote management server or the network device may discard the established communication session when a predetermined termination condition is satisfied.

[0031] Although the communication session established by the present invention poses a low security risk, maintaining a communication session at all times still poses a security risk. Therefore, it is desirable to discard the communication session when the remote management work for the network device is completed. In this case, the predetermined end condition may be, for example, that the necessary remote operation has ended, or that a predetermined time has passed since there was no response from the network device.

[0032] (7) A router according to another aspect is a router that relays between a private network and the Internet, randomly generates a UDP port number and an authentication key on the Internet side, transmits the generated UDP port number, authentication key, and its own device-specific information to a remote management server via a secure path, receives the authentication key transmitted from the remote management server at the UDP port of the UDP port number, and if the received authentication key matches the transmitted authentication key, establishes a communication session with the remote management server and accepts remote operation of the operating terminal via the communication session.

[0033] A router according to another aspect is a router invention corresponding to the case where a network device of the remote management system according to the one aspect includes a router function.

[0034] (8) A remote management method according to another aspect is a remote management method for performing remote management in a remote management system including a network device connected to a private network, a router relaying between the private network and the Internet, and a remote management server and an operation terminal connected to the Internet, the method including: a security information sending step in which the network device randomly generates a UDP port number and an authentication key for the network device and sends them in advance to the remote management server via a secure path together with device-specific information of the network device; a security information saving step in which the remote management server, upon receiving the UDP port number, the authentication key, and the device-specific information of the network device, saves the received UDP port number, the authentication key, and the device-specific information of the network device; a remote operation request step in which the operation terminal requests the remote management server to operate the network device, and the remote management server sends the authentication key to a UDP port of the network device corresponding to the device-specific information of the network device; a communication session establishing step in which the network device establishes a communication session between the network device corresponding to the device-specific information and the remote management server if the authentication key received at the UDP port matches the authentication key sent in advance; and a remote management execution step in which the operation terminal remotely manages the network device via the remote management server and the communication session.

[0035] A remote management method according to another aspect is a remote management method invention corresponding to the remote management system according to the one aspect. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a schematic diagram illustrating the overall configuration of a remote management system. [Figure 2] FIG. 2 is a schematic block diagram showing the configuration of a router. [Figure 3] FIG. 2 is a schematic block diagram showing the configuration of a remote management server. [Figure 4] FIG. 2 is a schematic block diagram showing the configuration of a network device (wireless LAN access point). [Figure 5] FIG. 2 is a schematic block diagram showing the configuration of an operation terminal. [Figure 6] 10 is a flowchart showing a flow of security information sharing. [Figure 7] 10 is a flowchart showing a flow of a remote operation request and remote management. [Figure 8] 10 is a flowchart illustrating a flow of remote management involving rebooting a network device. [Figure 9] 10 is a flowchart showing a flow of a remote operation request and remote management according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same components are designated by the same reference numerals. Furthermore, when the reference numerals are the same, the names and functions of the components are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0038] [composition] Figure 1 is a schematic diagram showing the overall configuration of a remote management system 100. In Figure 1, the remote management system 100 includes a network device 20 connected to a private network 10, a router 30 that relays between the private network 10 and the Internet 40, and a remote management server 50 and an operation terminal 60 connected to the Internet 40. In the following, in this embodiment, an example will be given in which the target of remote control is the network device 20, but the present invention also includes the case in which the target of remote control is the router 30. When the target of remote control is the network device 20, the pre-shared UDP port number (and authentication key and device-specific information) is the UDP port number (and authentication key and device-specific information) of the network device 20 in the private network 10, and when the target of remote control is the router 30, the pre-shared UDP port number (and authentication key and device-specific information) is the UDP port number (and authentication key and device-specific information) on the WAN side of the router 30. 1, one network device 20 is connected to the router 30, but multiple network devices 20 may be connected to the router 30. Also, in FIG. 1, one private network 10 and one router 30 are connected to the Internet 40, but multiple private networks 10 and multiple routers 30 may be connected to the Internet 40. Fig. 2 is a schematic block diagram showing the configuration of router 30. In Fig. 2, router 30 includes WAN-side communication unit 31, LAN-side communication unit 32, control unit 33, storage unit 34, display unit 35, and operation unit 36. WAN-side communication unit 31 is connected to Internet 40, and LAN-side communication unit 32 is connected to private network 10. Display unit 35 is composed of, for example, a small LCD display, LED, etc., and operation unit 36 ​​is composed of, for example, a toggle switch, push switch, etc. 3 is a schematic block diagram showing the configuration of the remote management server 50. In FIG. 3, the remote management server 50 includes a communication unit 51, a control unit 53, a storage unit 54, a display unit 55, and an operation unit 56. The communication unit 51 is connected to the Internet 40. The remote management server 50 may be a personal computer. In addition, a communication device such as a router may be connected between the communication unit 51 and the Internet 40.

[0039] 4 is a schematic block diagram showing the configuration of a network device 20. The network device 20 in FIG. 4 is an example of a wireless LAN access point, but the network device 20 may also be a NAS (Network Attached Storage), a network camera, a network game console, etc. Also included in the network device 20 are a network device 20 that has the functionality of a router 30, such as a wireless LAN router, and a router 30 alone. 4 includes a wireless communication unit 41, a LAN-side communication unit 42, a control unit 43, a storage unit 44, a display unit 45, and an operation unit 46. The display unit 45 is configured, for example, as a small liquid crystal display or an LED, and the operation unit 46 is configured, for example, as a toggle switch or a push switch. Note that the wireless LAN access point may be integrated with the router 30 and configured as a wireless LAN router. Fig. 5 is a schematic block diagram showing the configuration of an operation terminal 60. In Fig. 5, the operation terminal 60 includes a communication unit 61, a control unit 63, a storage unit 64, a display unit 65, and an operation unit 66. The communication unit 61 is connected to the Internet 40. The operation terminal 60 may be a personal computer. In addition, a communication device such as a router may be connected between the communication unit 61 and the Internet 40.

[0040] [Operation flow] The operation flow of remote management in the remote management system 100 will be described below with reference to a flowchart. 6 is a flowchart showing the flow of security information sharing, FIG. 7 is a flowchart showing the flow of a remote operation request and remote management, and FIG. 8 is a flowchart showing the flow of remote management involving rebooting of the network device 20. In the remote management system 100 of the present invention, security information (UDP port number, authentication key, and device-specific information) of the network device 20 is shared between the network device 20 and the remote management server 50. When the support department of the network device 20 sends a remote control request for the network device 20 corresponding to specific device-specific information from the operation terminal 60 to the remote management server 50, the remote management server 50 sends the authentication key to the UDP port of the network device 20. If the authentication key matches the authentication key shared in advance, the network device 20 establishes a communication session for remote control between the network device 20 and the remote management server 50, and the support department remotely manages the network device 20 from the operation terminal 60 via the communication session. Remote management includes, for example, acquiring the log of the network device 20, restarting the network device 20 as necessary, and checking the settings.

[0041] First, the flow of security information sharing will be explained step by step based on the flowchart in FIG. (S1) The network device 20 generates a UDP port number and an authentication key. The UDP port number is the number of the UDP port used when the remote management server 50 transmits the authentication key to the network device 20, and is randomly selected from the range of 32768-60999. The authentication key is preferably composed of binary data of, for example, 256 bits or more. (S2) The network device 20 transmits the UDP port number and the authentication key together with the device-specific information of the network device 20 to the remote management server 50 in advance via a secure path. Note that if the network device 20 does not include the functionality of the router 30 and is connected to the private network 10 side of the router 30, the UDP port number, authentication key, and device-specific information of the network device 20 are NAPT converted by the router 30 and transmitted to the remote management server 50. In this case, it is preferable that the router 30 open a port on the WAN side for connecting to the network device 20. The unique information may be, for example, the model number and serial number of the network device 20, or the MAC address (if the MAC address is fixed). As a secure route, it is desirable to use MQTT communication, which has enhanced security using TLS (Transport Layer Security), an encrypted communication protocol. Steps S1 and S2 correspond to the security information transmission step. (S3) The remote management server 50 stores the received UDP port number and authentication key in the storage unit 54 in association with the device-specific information of the network device 20. Step S3 corresponds to the security information storage step.

[0042] It is preferable to share security information (pre-sharing of UDP port numbers, authentication keys, etc.) when the network device 20 is installed in the private network 10 and becomes accessible to the Internet (WAN). Security information may also be shared when there is a change in the WAN or private IP address, or on a regular basis such as daily, weekly, or monthly.

[0043] Next, the flow of a remote operation request and remote management will be described with reference to the flowchart of FIG. (S4) The operation terminal 60 transmits a request for remote operation of the specific network device 20 to the remote management server 50. (S5) The remote management server 50 retrieves from the storage unit 54 the UDP port number and authentication key corresponding to the device-specific information of the network device 20 that received the remote operation request, and transmits the authentication key to the corresponding UDP port of the router 30. In this case as well, if the network device 20 is connected to the private network 10 side of the router 30, the authentication key is NAPT converted by the router 30 and transmitted to the network device 20. Steps S4 and S5 correspond to the remote operation request step. (S6) The network device 20 checks whether the authentication key sent to the UDP port number previously sent matches the authentication key previously sent. (S7, S8) If the authentication keys match, the network device 20 establishes a communication session for remote control between the network device 20 and the remote management server 50, and if they do not match, ends the process. Steps S6 to S8 correspond to the communication session establishment step. (S9) The operation terminal 60 instructs the remote management server 50 to perform the necessary remote operation via the communication session. Step S9 corresponds to the remote management execution step. (S10, S11) When the necessary remote operation is completed, the network device 20 discards the communication session. The termination of the communication session conforms to normal TCP operation, and even if there is no response from the network device 20 for some reason, the communication session will terminate after a predetermined time has elapsed. Therefore, the predetermined end condition corresponds to the end of the necessary remote operation or the lapse of a predetermined time since there was no response from the network device 20.

[0044] When the network device 20 is rebooted as part of remote management, the communication session is discarded. For this reason, a special flow is required for remote management when rebooting the network device 20. FIG. 8 shows the flow of remote management when the network device 20 is rebooted. (S21) When restarting the network device 20, first, the network device 20 saves the data of the communication session. (S22) The network device 20 is restarted. (S23) After the network device 20 has been successfully restarted, it checks whether there is any saved data for the communication session, and if there is no saved data, the process ends. (S24) If there is saved data, the communication session is re-established using that data. The subsequent steps S9-S11 are the same as those in FIG.

[0045] (Security of the remote management system 100) For the security of the remote management system 100, it is important that the UDP port number of the network device 20 cannot be detected by the outside, and that the authentication key cannot be deciphered. First, there is port scanning, which detects port numbers. This involves sending UDP packets or similar to a target port to detect the status of the service waiting on that port. In response to this, even if a packet is sent to the corresponding port, the network device 20 does not respond or send any data, so that the packet cannot be distinguished from other ports that are not waiting for anything. In addition, to ensure the confidentiality of the authentication key, the authentication key is composed of binary data of 256 bits or more, reducing the risk of security being breached by sending a random authentication key.

[0046] (Modifications for improved security) FIG. 9 is a flowchart showing a flow of a remote operation request and remote management according to a modified example for improving security. In the flow of Figure 7, after authenticating using the authentication key sent to the corresponding UDP port, the network device 20 immediately establishes a communication session, but in the flow of the modified example of Figure 9, after authenticating using the authentication key sent to the corresponding UDP port, the network device 20 sends a newly generated UDP port number and authentication key to the remote management server 50, and then authenticates again using the authentication key returned from the remote management server 50 before establishing a communication session. In this case, it takes twice as long to search for port numbers using UDP scanning and to decrypt the authentication key, but the second port number and authentication key are generated immediately, so there is no time for searching, decrypting, or leaking, which further improves the security level. Below, the flowchart in FIG. 9 will be explained step by step. S1 to S7 are the same as those in the flowchart of FIG. (S31) If the authentication keys match, the network device 20 randomly generates a second UDP port number and a second authentication key. (S32) The network device 20 transmits the generated second UDP port number and second authentication key together with the device-specific information of the network device 20 to the remote management server 50 via a secure path. (S33) The remote management server 50 transmits the received second authentication key to the corresponding UDP port of the network device 20. (S34, S35) The network device 20 compares the transmitted second authentication key with the received second authentication key, and if they do not match, ends the process. If the authentication keys match, steps S8 to S11 are the same as those in FIG. By using the flow of the above modification, the level of security can be further improved.

[0047] (Dynamic DNS support) In recent years, global IP addresses of routers and the like are assigned different IP addresses by providers mainly when the router is powered off and on again, when no communication has been performed for a certain period of time, etc. Therefore, even in communications between the network device 20 and the remote management server 50, the source and / or destination IP addresses change dynamically. In this case, by specifying a domain name instead of an IP address for the source and / or destination and using a dynamic domain name system (Dynamic Domain Name System), it is possible to reliably specify the IP addresses of the source and / or destination. The remote management system 100 of the present invention also uses a domain name and a dynamic DNS to communicate between the network device 20 and the remote management server 50.

[0048] In the present invention, the remote management system 100 corresponds to the "remote management system", the private network 10 corresponds to the "private network", the network device 20 corresponds to the "network device", the Internet 40 corresponds to the "Internet", the router 30 corresponds to the "router", the remote management server 50 corresponds to the "remote management server", and the operation terminal 60 corresponds to the "operation terminal".

[0049] Although a preferred embodiment of the present invention has been described above, the present invention is not limited thereto. It will be understood that various other embodiments can be made without departing from the spirit and scope of the present invention. Furthermore, although the actions and effects of the configuration of the present invention are described in this embodiment, these actions and effects are merely examples and do not limit the present invention. [Explanation of symbols]

[0050] 10 Private Networks 20 Network Devices 30 Router 40 Internet 50 Remote Management Server 60 Operation terminal 100 Remote Management System

Claims

1. A remote management system including a network device connected to a private network, a router that relays between the private network and the Internet, and a remote management server and an operation terminal connected to the Internet, the network device randomly generates a UDP port number and an authentication key for the network device and transmits them to the remote management server in advance via a secure path together with device-specific information for the network device; when the remote management server receives the UDP port number, the authentication key, and the device specific information of the network device, it stores the received UDP port number, the authentication key, and the device specific information of the network device; When the operation terminal requests the remote management server to operate the network device, the remote management server transmits the authentication key to a UDP port of the network device corresponding to the device-specific information of the network device; When the authentication key received at the UDP port matches the authentication key previously transmitted, the network device establishes a communication session between the network device corresponding to the device-specific information and the remote management server; The operation terminal remotely manages the network device via the remote management server and the communication session.

2. A remote management system as described in claim 1, wherein if the authentication key received on the UDP port does not match the authentication key previously sent, the network device does not establish a communication session, and the network device does not respond or send any information in response to a port scan.

3. The remote management system according to claim 1 , wherein the network device is a wireless LAN access point or a NAS.

4. The remote management system of claim 1 , wherein the network device includes the functionality of the router.

5. The remote management system of claim 1 , wherein the secure path and the communication session use Transport Layer Security (TLS).

6. The remote management system according to claim 1 , wherein the remote management server or the network device discards the established communication session when a predetermined termination condition is satisfied.

7. A router that relays between a private network and the Internet, A UDP port number on the Internet side and an authentication key are randomly generated, transmitting the generated UDP port number, the authentication key, and the device's own device-specific information to a remote management server via a secure path; receiving the authentication key transmitted from the remote management server at the UDP port of the UDP port number, and if the received authentication key matches the transmitted authentication key, establishing a communication session with the remote management server; A router that accepts remote control of the operation terminal via the communication session.

8. A remote management method for performing remote management in a remote management system including a network device connected to a private network, a router relaying between the private network and the Internet, and a remote management server and an operation terminal connected to the Internet, comprising: a security information transmission step in which the network device randomly generates a UDP port number and an authentication key for the network device and transmits them in advance to the remote management server via a secure path together with device-specific information for the network device; a security information storage step of storing, when the remote management server receives the UDP port number, the authentication key, and the device specific information of the network device, the received UDP port number, the authentication key, and the device specific information of the network device; a remote operation request step in which the operation terminal requests the remote management server to operate the network device, and the remote management server transmits the authentication key to a UDP port of the network device corresponding to the device-specific information of the network device; a communication session establishment step of establishing a communication session between the network device corresponding to the device-specific information and the remote management server when the authentication key received at the UDP port matches the authentication key previously transmitted by the network device; a remote management execution step in which the operation terminal remotely manages the network device via the remote management server and the communication session.

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