Proxy response device and proxy response method

Abstract

Ensure that devices connected to the LAN can be reliably accessed using their hostnames. [Solution] The hostnames and MAC addresses of devices connected to LAN2 are associated and registered in the device information file 104. When a request for confirmation of duplicate IP addresses (GARP, DAD-NS) is received, the address information collection unit 112 functions and updates the address information file 105 by associating the IP addresses and MAC addresses contained therein. When a destination resolution request (mDNS) including a hostname is received, the name resolution unit 113 functions, identifies the MAC address by referring to the device information file 104 from the hostname, and identifies the IP address by referring to the address information file 105 from the identified MAC address. The resolution result provision unit 114 notifies the sender of the destination resolution request (mDNS) of this identified IP address.

Description

Technical Field

[0003]

[0001] This invention relates to an apparatus and a method for enabling identification of a destination by a host name when communicating between devices connected to a LAN (Local Area Network).

Background Art

[0002] Patent Document 1, which will be described later, discloses an invention related to a router or the like for enabling access to communication devices in a LAN using the same name from both the WAN (Wide Area Network) side and the LAN side. The router disclosed in Patent Document 1 connects a WAN and a LAN including a communication device A and a communication terminal T to each other. The router includes a storage unit X that stores, in association with each other, the name of the communication device A associated with a global IP (Internet Protocol) address in a wide area network and the local IP address of the communication device A. When there is an access to the communication device A using the name from the communication terminal T, it includes a name resolution unit Y that returns the local IP address of the communication device A stored in the storage unit X to the communication terminal T.

[0003] In this way, by storing the name assigned to a device and the local IP address in association with each other, when there is an access request using the name of the device, the local IP address can be specified from the name and returned to the requester. Therefore, the requester device can access the target device using the returned IP address. That is, the user of the requester device can access by the name of the target device without being aware of the IP address of the target device.

Prior Art Documents

[0005] Traditionally, using a DNS (Domain Name System) server has enabled access between devices connected to a LAN using hostnames. A hostname is a name assigned to identify a computer on a network. Figure 10 illustrates an example of a conventional network system that allows access between devices using hostnames. As shown in Figure 10, a router 301 is provided between the Internet 200 and LAN 300. Router 301 is a device that performs relay functions between the Internet 200 and LAN 300, and it also has a DHCP (Dynamic Host Configuration Protocol) server function. It can assign IP addresses to devices connected to LAN 300.

[0006] In this example, router 301 assigns fixed IP addresses to devices connected to LAN 300. Therefore, once a device connected to LAN 300 receives an IP address from router 301, it will not change and will always be able to use the same IP address. In the example shown in Figure 10, the DNS server 304 is assigned the IP address "192.168.1.10", and the PC (Personal Computer) 302 is assigned the IP address "192.168.1.20". In addition, device 303 is assigned the IP address "192.168.1.30" and has "host-x" set as its hostname.

[0007] In this case, the DNS server 304 is configured, for example, by the network administrator, to associate the hostname "host-x" of device 303 with the IP address "192.168.1.30" of device 303. Furthermore, each device connected to LAN 300 is configured to access the DNS server 304 for hostname resolution. Now, suppose PC 302 attempts to access device 303 using its hostname "host-x". As indicated by the arrow 401 from PC 302 to DNS server 304, PC 302 requests DNS server 304 to resolve the IP address of the hostname "host-x".

[0008] In response, DNS server 304 identifies the IP address of device 303 from the hostname and IP address configured on its own machine. As indicated by arrow 402 from DNS server 304 to PC 302, DNS server 304 returns the identified IP address, "102.168.1.30", to PC 302 as the resolution result. As a result, as indicated by arrow 403 from PC 302 to device 303, PC 302 can access device 303 using the IP address of device 303 from DNS server 304. In this case, the user of PC 302 can access device 303 by its hostname without being aware of its IP address at all. Hostnames are usually composed of a few characters that are easy for the user to understand, so the user can easily specify the target device and access it.

[0009] However, as mentioned above, with the conventional method, (1) IP addresses must be fixed and assigned. This is because if IP addresses were to change at predetermined intervals, such as when the power is turned on, managing them in association with hostnames would become complicated. Also, (2) a DNS server must be set up for hostname resolution, and the hostnames and IP addresses of each device connected to LAN300 must be associated with this DNS server and configured. Furthermore, (3) each device connected to LAN300 must be configured to access DNS server 304 for hostname resolution. Thus, in the case of the network system shown in Figure 10, the user has to perform configuration work related to the correspondences described in (1) to (3) above, which makes it time-consuming and troublesome to set up the environment.

[0010] Furthermore, the network system described using Figure 10 also presents the problem of not being able to support IPv6 (Internet Protocol Version 6) IP addresses. IPv6 has a self-configuration function (stateless address auto-configuration), which allows the device to use an IP address generated by the device using information from the network and the device itself. Therefore, since the IP address is generated by the device using information from the network and the device itself at times such as when the device is powered on, it is usually not possible to use a fixed IP address.

[0011] Therefore, one might consider recording the mapping between hostnames and IP addresses in the hosts file of each device to enable support for IPv6 IP addresses, allowing access via hostname. However, if the IP address is automatically configured, the IP address is unknown and cannot be recorded in the hosts file. Furthermore, even if the IP address is known, it is cumbersome to re-record the mapping between hostnames and IP addresses every time the IP address changes. In addition, since a hosts file exists on each device, centralized management is not possible. In other words, the more devices connected to the LAN, the less practical hostname access using the devices' hosts files becomes.

[0012] In view of the above points, the present invention aims to eliminate the above-mentioned problems and to ensure that devices connected to a LAN can be reliably accessed using hostnames. [Means for solving the problem]

[0013] To solve the above problems, the proxy response device of the invention described in claim 1 is A proxy response device provided for a LAN (Local Area Network) to which multiple devices configured with IP (Internet Protocol) addresses are connected, A device information storage means that stores and maintains, in association with an arbitrarily set hostname and the MAC (Media Access Control) address of each of the multiple devices, When an address information collection means receives a confirmation request from each of the multiple aforementioned devices to check for duplicate IP addresses, it associates the IP address and MAC address of the device included in the confirmation request and records them in the address information storage means. Name resolution means that, upon receiving a destination resolution request including a hostname from the device connected to the LAN, refers to the device information storage means based on the hostname to identify the MAC address, and refers to the address information storage means based on the MAC address to identify the IP address, Resolution result providing means that notifies the device that sent the destination resolution request of the IP address identified by the name resolution means, It is characterized by having the following features.

[0014] According to the proxy response device of the invention described in claim 1, the device information storage means stores and associates an arbitrarily assigned hostname and the device's MAC address for each of a plurality of devices connected to the LAN. When a request for confirmation of duplicate IP addresses is received from each of the plurality of devices, the address information collection means associates the IP address and MAC address of the device included in the confirmation request and records it in the address information storage means. Suppose a destination resolution request including a hostname is received from a device connected to the LAN. In this case, the name resolution means references the device information storage means based on the hostname to identify the corresponding MAC address, and then references the address information storage means based on the MAC address to identify the corresponding IP address. The IP address identified (resolved) by the name resolution means is notified to the device that sent the destination resolution request by the resolution result providing means. [Effects of the Invention]

[0015] According to this invention, it is possible to reliably access devices connected to a LAN using their hostnames without requiring any effort from the users of the devices connected to the LAN or the network administrators of the LAN. [Brief explanation of the drawing]

[0016] [Figure 1] This is a diagram illustrating an example of the configuration of the network system according to the embodiment. [Figure 2] It is a block diagram for explaining a configuration example of the proxy response device according to the embodiment. [Figure 3] It is a diagram for explaining an example of stored data in the device information file of the proxy response device. [Figure 4] It is a diagram for explaining an example of stored data in the address information file of the proxy response device. [Figure 5] It is a sequence diagram for explaining the processing performed in the network system according to the embodiment. [Figure 6] It is a diagram showing the format of the GARP message. [Figure 7] It is a diagram showing the format of the DAD-NS message. [Figure 8] It is a diagram showing the format of the mDNS protocol. [Figure 9] It is a diagram showing the format of the LLMNR protocol. [Figure 10] It is a diagram for explaining an example of a conventional network system in which access using a host name is possible between devices.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, an embodiment of the device and method of this invention will be described with reference to the drawings. In the embodiment described below, a case where a device to which the device and method according to this invention are applied is connected to a LAN formed in a company office will be described as an example.

[0018] [Configuration Example of Network System] Figure 1 is a diagram illustrating an example of the configuration of a network system according to an embodiment. In Figure 1, the proxy response device 1 is an embodiment of the device and method according to this invention and is connected to LAN2. As shown in Figure 1, various devices are connected to LAN2 that are assigned IP addresses and can communicate with each other, such as PC3(1), device3(2), PC3(3), etc. Note that device3(2) is assumed to be a smartphone or tablet PC. In Figure 1, different devices are written as PC3(1), device3(2), PC3(3), etc., but all network devices (devices) connected to LAN2 can be said to be device3. Therefore, when it is not necessary to specify the type of device such as PC, it may be written as device3(1), 3(2), 3(3), etc.

[0019] Furthermore, a router 4 is provided between LAN2 and the Internet 5. Router 4 is responsible for relaying data between LAN2 and the Internet 5, and in this embodiment, it is equipped with DNS server functionality and DHCP server functionality. As a result, each of the PC3(1), device3(2), PC3(3), ... connected to LAN2 can access the Internet 5 via the router and communicate with various server devices on the Internet 5.

[0020] In the network system shown in Figure 1, each device 3(1), 3(2), 3(3), ... is assigned an IP address by the DHCP server function of router 4. Specifically, as shown in Figure 1, PC3(1) is assigned the IPv4 IP address "192.168.1.101" and the IPv6 IP address "2001:100:200:300:1:1:1:1". Similarly, device 3(2) is assigned the IPv4 IP address "192.168.1.102" and the IPv6 IP address "2001:100:200:300:2:2:2:2". Additionally, PC3(3) is assigned both the IPv4 IP address "192.168.1.103" and the IPv6 IP address "2001:100:200:300:3:3:3:3".

[0021] Furthermore, each device 3(1), 3(2), 3(3), ... is pre-configured with a MAC address that uniquely identifies it at the time of shipment. Specifically, as shown in Figure 1, the MAC address of PC3(1) is "aa:aa:aa:aa:aa:aa". The MAC address of device 3(2) is "bb:bb:bb:bb:bb:bb". The MAC address of PC3(3) is "cc:cc:cc:cc:cc:cc". However, IP addresses and MAC addresses do not represent meaning that humans can easily grasp at a glance, and they are also long in length, making them unsuitable for users to input and use without making mistakes.

[0022] Therefore, each device 3(1), 3(2), 3(3), ... is assigned a hostname that can be arbitrarily set by the user. In the network system shown in Figure 1, PC3(1) is assigned the hostname "alpha". Device 3(2) is assigned the hostname "beta". PC3(3) is assigned the hostname "gamma". In this embodiment, the hostnames assigned to each device 3(1), 3(2), 3(3), ... are Greek letter pronunciations. This allows the user to understand that PC3(1) is "alpha", device 3(2) is "beta", and PC3(3) is "gamma", and to input them through each device to specify the desired destination.

[0023] The proxy response device 1 then implements a name resolution function, which is the function of identifying an IP address from a hostname. Using the name resolution function of the proxy response device 1, for example, suppose PC3(1) uses "beta" as the hostname of the target device to access it. In this case, the name resolution function of the proxy response device 1 identifies the IP address of device 3(2) from the hostname "beta". The resulting IP address is provided to PC3(1), and PC3(1) can then use this IP address to access device 3(2).

[0024] In this way, users of various devices connected to LAN2 can directly specify and access the device used by the target party from their own device and communicate with it. In this case, to specify the target party easily and reliably, it is possible to use a hostname instead of an IP address. A specific example of the configuration of a proxy response device equipped with such a name resolution function will be described.

[0025] [Example of a proxy response system configuration] Figure 2 is a block diagram illustrating an example configuration of the proxy response device according to the embodiment. The connection terminal 101T constitutes the connection terminal to LAN2. LANI / F (Interface) 101 is the part that performs communication processing through LAN2. That is, LANI / F 101 receives signals addressed to the local device that are transmitted via LAN2, converting them into a signal format that can be processed by the local device. LANI / F 101 also converts signals to be transmitted from the local device into a signal format for transmission, sends them to LAN2, and transmits them to the other party. Therefore, when communicating with a party connected to LAN2, the communication is performed through the connection terminal 101T and LANI / F 101.

[0026] The control unit 102, although not shown in the diagram, is a microprocessor comprising a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), non-volatile memory, etc., and controls each part of the proxy response device 1. For example, the non-volatile memory of the control unit 102 stores the MAC address and serial number of the proxy response device 1. The storage device 103 is a device consisting of a recording medium and its driver, such as an HDD (Hard Disk Drive) or SSD (Solid State Drive), and performs recording, reading, modification, and deletion of various data on the recording medium. In addition to storing necessary data and programs, the storage device 103 is also used as a working area to temporarily store intermediate data generated in various processes.

[0027] The device information file 104 stores and maintains an arbitrarily set hostname and the device's MAC address for each of the devices 3(1), 3(2), 3(3), ... connected to LAN2, in association with each device. Figure 3 is a diagram illustrating an example of the data stored in the device information file 104 of the proxy response device 1. As shown in Figure 3, the device information file 104 includes a hostname field for storing hostnames and a MAC address field for storing MAC addresses. As explained using Figure 1, each of the devices 3(1), 3(2), 3(3), ... connected to LAN2 is assigned a hostname, for example, by the network administrator, based on the pronunciation of Greek letters. In addition, each of the devices 3(1), 3(2), 3(3), ... connected to LAN2 is assigned a MAC address at least at the time of shipment, which can be confirmed by referring to the information in the non-volatile memory of the control unit 102.

[0028] Therefore, for example, when a network administrator installs a device connected to LAN2, they check the MAC address of the device, associate the checked MAC address with an arbitrarily assigned hostname, and register it in the device information file 104. This allows an arbitrarily assigned hostname to be associated with a MAC address that can uniquely identify each device. In the example shown in Figure 3, the hostname "alpha" is associated with the MAC address "aa:aa:aa:aa:aa:aa". As shown in Figure 1, this MAC address is assigned to PC3(1), so it can be seen that the hostname "alpha" has been assigned to PC3(1).

[0029] Furthermore, in the example shown in Figure 3, the hostname "beta" is associated with the MAC address "bb:bb:bb:bb:bb:bb". As shown in Figure 1, this MAC address is assigned to device 3(2), so it can be seen that the hostname "beta" has been assigned to device 3(2). Also, in the example shown in Figure 3, the hostname "gamma" is associated with the MAC address "cc:cc:cc:cc:cc:cc". As shown in Figure 1, this MAC address is assigned to PC3(3), so it can be seen that the hostname "gamma" has been assigned to PC3(3). Note that the device information file 104 shown in Figure 3 can also contain other information such as the name of the device user and the installation location.

[0030] The address information file 105 stores and maintains the assigned IP address and the MAC address of each device 3(1), 3(2), 3(3), ... connected to LAN2, in association with each device. Figure 4 is a diagram illustrating an example of the data stored in the address information file 105 of the proxy response device 1. As shown in Figure 4, the address information file 105 includes a MAC address field for storing the MAC address of each device and an IP address field for storing the IP address assigned to each device. The data stored in the address information file 105 is not stored manually by a network administrator or other person. As will be described in more detail later, when an IP address is assigned to each device, the MAC address and IP address included in the IP address duplication confirmation request sent from each device are extracted and registered (updated) in the address information file 105.

[0031] As shown in Figure 4, the MAC address "aa:aa:aa:aa:aa:aa" is associated with the IPv4 IP address "192.168.1.101" and the IPv6 IP address "2001:100:200:300:1:1:1:1". Similarly, the MAC address "bb:bb:bb:bb:bb:bb" is associated with the IPv4 IP address "192.168.1.102" and the IPv6 IP address "2001:100:200:300:2:2:2:2". Furthermore, the MAC address "cc:cc:cc:cc:cc:cc" is associated with the IPv4 IP address "192.168.1.103" and the IPv6 IP address "2001:100:200:300:3:3:3:3". This means that if you know the MAC address, you can also find out the IP address assigned to the device identified by that MAC address.

[0032] The device information setting unit 111 functions when it receives a device information registration request from a network administrator's PC connected to LAN2 via the connection terminal 101T and LANI / F 101. The device information setting unit 111 processes the device information included in the received registration request and registers it in the device information file 104. The device information includes at least the hostname and MAC address.

[0033] The address information collection unit 112 functions when it receives a request to check for duplicate IP addresses sent from each device connected to LAN2 via the connection terminal 101T and LANI / F 101, at the time an IP address is assigned to each device connected to LAN2. The address information collection unit 112 extracts the MAC address and IP address included in the request and registers (updates) them in the address information file 105.

[0034] The name resolution unit 113 functions when it receives a destination resolution request containing a hostname from devices 3(1), 3(2), 3(3), ... connected to LAN2 via the connection terminal 101T and LANI / F 101. Based on the hostname included in the destination resolution request, the name resolution unit 113 refers to the device information file 104 to identify the corresponding MAC address. Furthermore, based on the identified MAC address, the name resolution unit 113 refers to the address information file 105 to identify the corresponding IP address.

[0035] The resolution result provision unit 114 sends the IP address identified by the name resolution unit 113 to LAN2 via LANI / F 101 and connection terminal 101T, providing it to the device that sent the destination resolution request. As a result, the device that sent the destination resolution request including a hostname can obtain the IP address of the target destination corresponding to that hostname, and can use this IP address to access the target destination. In this case, the user of the device that sent the destination resolution request including a hostname can access the target destination device by specifying it by hostname, without having to be aware of the target destination's IP address at all.

[0036] [Processing of the network system including proxy response device 1] Next, we will describe the process for enabling access by specifying the destination using a hostname, which is performed in the network system shown in Figure 1, including the proxy response device 1 explained using Figures 2 to 4. Figure 5 is a sequence diagram illustrating the process performed in the network system of the embodiment. PC3(1) connected to LAN2 forms a confirmation request to check for duplicate IP addresses at the time an IP address is assigned to itself, and sends it to devices connected to LAN2 using a broadcast method (step S1).

[0037] IP addresses are assigned at the following times: when a device starts up, when a new connection is made to LAN2, when the IP address lease period is renewed, and when an IP address is manually configured. "When a device starts up" is because when a device starts up, the DHCP server function of Router 4 operates and an IP address is automatically assigned. "When a new connection is made to the network" is also relevant because even devices that are already running need to obtain an IP address appropriate for the new network when connecting to a new network. In this case as well, the router's DHCP server function automatically assigns an IP address.

[0038] Furthermore, "when the IP address lease period is renewed" is a common occurrence in DHCP servers, where the lease period (validity period) of an IP address is set. When this lease period ends, the device requests to be reassigned the same IP address. At this time, the router's DHCP server function also assigns an IP address to the device. "When the IP address is manually set" refers to cases where a network administrator manually sets, for example, a static IP address, and this can also be considered an IP address assignment timing. At such IP address assignment timings, PC3(1) forms a confirmation request to check for IP address duplication and broadcasts it (step S1).

[0039] In step S1, if PC3(1) is assigned an IPv4 address, it forms a GARP (Gratuitous Address Resolution Protocol) message and sends it to LAN2. The GARP message notifies other devices of the IP address assigned to the sending device by broadcasting an ARP request using the IP address assigned to it by the sending PC3(1). If another device on LAN2 that receives the GARP message is using the same IP address, a response is returned, and the duplication is detected. Figure 6 shows the format of the GARP message. As shown in Figure 6, the GARP message includes the MAC address (Sender Hardware Address) and IP address (Sender Protocol Address) of the sending PC3(1).

[0040] Furthermore, in step S1, if PC3(1) is assigned an IPv6 IP address, it forms a DAD (Duplicate Address Detection)-NS (Neighbor Solicitation) message and sends it to LAN2. The DAD-NS message is sent by the source PC3(1) via broadcast to check if there are any other devices with the automatically configured IP address. If there is a device with the same IP address as the one included in the DAD-NS message, a response (Neighbor Advertisement) is returned, allowing the duplication to be detected. Figure 7 shows the format of the DAD-NS message. As shown in Figure 7, the DAD-NS message also includes the MAC address (recorded as Options) and IP address (Target Address) of the source PC3(1).

[0041] PC3(1) may be assigned both an IPv4 and an IPv6 IP address, in which case both GARP and DAD-NS messages are sent. When a proxy response device receives a GARP or DAD-NS message sent from PC3(1), it updates the address information file 105 (step S2). In step S2, the address information collection unit 112 functions to extract the MAC address and IP address present in those messages and update the address information file 105. That is, if the same MAC address already exists, the existing information is deleted and the new information (MAC address and IP address) is recorded. If the same MAC address does not already exist, the new information (MAC address and IP address) is registered (added).

[0042] Here, we have described PC3(1), but device 3(2) also forms GARP messages (Figure 6) and DAD-NS messages (Figure 7) when an IP address is assigned, and transmits them using a broadcast method (step S3). Upon receiving these messages, the proxy response device 1 activates the address information collection unit 112, extracts the MAC address and IP address present in those messages, and updates the address information file 105 (step S4).

[0043] Furthermore, PC3(3) also forms GARP messages (Figure 6) and DAD-NS messages (Figure 7) when an IP address is assigned, and transmits them via broadcast (Step S5). Upon receiving these messages, the proxy response device 1 activates the address information collection unit 112, extracts the MAC address and IP address present in those messages, and updates the address information file 105 (Step S6).

[0044] In this embodiment of the network system, all devices connected to LAN2 form GARP messages (Figure 6) and DAD-NS messages (Figure 7) when an IP address is assigned, and transmit them via broadcast. Upon receiving these messages, the proxy response device 1 activates the address information collection unit 112, extracts the MAC address and IP address present in those messages, and updates the address information file 105. This allows all devices connected to LAN2 to be managed in association with their MAC addresses and the most recently assigned IP addresses. Furthermore, whether an IPv4 IP address or an IPv6 IP address is assigned to a device, it can be managed in association with the MAC address in the address information file 105, as explained using Figure 4.

[0045] Furthermore, assume that the proxy response device 1 already has the address information file 105, as explained using Figure 4, and the device information file 104, as explained using Figure 3, prepared. In this case, assume that the user of PC3(1) attempts to access the destination using the hostname "beta". In response to the user's input, PC3(1) will specifically form and send a destination resolution request using the mDNS (Multicast Domain Name System) protocol. The mDNS protocol is a protocol that resolves the names of devices and services within a local network. When devices find other devices within the network, they send requests to multicast addresses and receive responses to perform name resolution.

[0046] Figure 8 shows the format of the mDNS protocol. The mDNS protocol is used for both queries and answers. When the mDNS protocol is used for a query, the hostname "beta" is entered in the "Queries" field of the mDNS format shown in Figure 8(A). As a result, PC3(1) configures the protocol "mDNS query beta.local", which requests resolution of the hostname "beta", and sends it to LAN2 using multicast (step S7).

[0047] When the proxy response device 1 receives the destination resolution request "mDNS query beta.local" from PC3(1), the name resolution unit 113 functions and performs destination lookup processing (name resolution processing) based on the hostname (step S8). Specifically, the name resolution unit 113 refers to the device information file 104 based on the hostname "beta" recorded in the "Queries (query information)" of the received mDNS protocol and identifies the MAC address corresponding to the hostname "beta". Next, the name resolution unit 113 refers to the address information file 105 based on the identified MAC address and identifies the IP address corresponding to that MAC address.

[0048] After this, the proxy response device 1's resolution result provision unit 114 functions and notifies PC3(1), the source of the destination resolution request "mDNS query beta.local", of the identified IP address (step S9). In this case, the proxy response device 1 returns a response using the mDNS protocol and an "Answers" record. That is, if the identified IP address is IPv4, the proxy response device 1 returns a response using the "IN A record" shown in Figure 8(B), and if the identified IP address is IPv6, it returns a response using the "IN AAAA record" shown in Figure 8(C).

[0049] In the mDNS protocol, an "IN A record" associates a hostname with an IPv4 address, while an "IN AAAA record" associates a hostname with an IPv6 address. In Figures 8(B) and (C), "IN" in "Class" indicates the "Internet Class," and "TTL" indicates the cache expiration time, which in this example is "120 seconds."

[0050] The requesting PC3(1) can obtain the IP address of device 3(2) assigned the hostname "beta" from the proxy response device 1 through the "IN A record" and "IN AAAA record" of the mDNS protocol, which are notifications of the destination IP address. As a result, PC3(1), which sent the destination resolution request by hostname, can obtain the IP address of device 3(2) whose hostname is "beta", and use this to access and connect to device 3(2) (step S10).

[0051] [Using the LLMNR protocol] Here, we have used the mDNS protocol to perform name resolution, which identifies IP addresses using hostnames, but this is not the only option. In relatively small LAN systems, the LLMNR (Link-Local Multicast Name Resolution) protocol can be used instead of the mDNS protocol for name resolution. The LLMNR protocol is a protocol that performs name resolution within a link-local network (within the same subnet). It can be used for similar purposes as the mDNS protocol.

[0052] Figure 9 shows the format of the LLMNR protocol. As can be seen by comparing Figure 9 with Figure 8(A), the format of the LLMNR protocol (Figure 9) is almost identical to the format of the mDNS protocol (Figure 8(A)). When performing name resolution within the same subnet aggregated by a single router, the LLMNR protocol can be used instead of the mDNS protocol.

[0053] [Effects of the embodiment] According to the proxy response device of the embodiment described above, the hostnames arbitrarily assigned to each of the multiple devices connected to LAN2 are associated with the MAC addresses of those devices and managed in the device information file 104. Furthermore, the latest IP addresses assigned to each of the multiple devices connected to LAN2 are associated with the MAC addresses of those devices and managed in the address information file 105. As a result, if the hostname is known, it becomes possible to identify the IP address using the MAC address as relay information, and success using hostnames can be achieved between devices connected to LAN2. In this case, the IP addresses can be either IPv4 or IPv6.

[0054] This allows the proxy response device 1 to handle name resolution even if various devices connected to LAN2 do not support, for example, the mDNS protocol or LLMNR protocol. Therefore, it becomes possible to access devices that do not support the mDNS protocol or LLMNR protocol using their hostnames. Of course, devices that do support the mDNS protocol or LLMNR protocol can also be accessed using their hostnames.

[0055] Therefore, there is no need to use a fixed IP address, and it can support both IPv4 and IPv6 IP addresses. Device users can access the target device by hostname without having to be aware of its IP address. It is possible that some devices connected to LAN2 may have a default hostname. However, by using the proxy response device 1, users on the LAN2 side can set a user-friendly hostname in addition to the default hostname and use that instead.

[0056] In the embodiment described above, the process of associating the hostnames arbitrarily assigned to each of the multiple devices connected to LAN2 with the MAC addresses of those devices and registering them in the device information file 104 is performed by the network administrator. However, the process of associating the latest IP addresses assigned to each of the multiple devices connected to LAN2 with the MAC addresses of those devices and updating the address information file 105 is performed automatically by the address information collection unit 112. Therefore, the network administrator does not need to be aware of the IP addresses of the devices connected to LAN2.

[0057] [Differentiation] In the embodiment described above, a proxy response device 1 equipped with a name resolution function is provided to LAN2, but the invention is not limited to this. The functions of the proxy response device 1 can also be implemented in network devices such as DNS servers, routers, and DHCP servers connected to the LAN. For example, if the functions of the proxy response device 1 of this invention are implemented in a DNS server, it becomes unnecessary for devices to send destination resolution requests using hostnames in a broadcast manner, and they can be sent to the DNS server in a unit cast manner. Therefore, destination resolution requests using hostnames can be prevented from being sent to unrelated devices. Accordingly, the proxy response device 1 according to this invention can be configured as a standalone device and connected to the LAN. [Explanation of symbols]

[0058] 1...Proxy response device, 101T...Connection terminal, 101...LAN interface, 102...Control unit, 103...Storage device, 104...Device information file, 105...Address information file, 111...Device information setting unit, 112...Address information collection unit, 113...Name resolution unit, 114...Resolution result provision unit, 2...LAN, 3(1), 3(3)...PC, 3(2)...Device, 4...Router, 5...Internet

Claims

1. A proxy response device provided for a LAN (Local Area Network) to which multiple devices configured with IP (Internet Protocol) addresses are connected, A device information storage means that stores and maintains, in association with an arbitrarily set hostname and the MAC (Media Access Control) address of each of the multiple devices, When an address information collection means receives a confirmation request from each of the multiple aforementioned devices to check for duplicate IP addresses, it associates the IP address and MAC address of the device included in the confirmation request and records them in the address information storage means. When a name resolution request including a hostname is received from the device connected to the LAN, the name resolution means refers to the device information storage means based on the hostname to identify the MAC address, and refers to the address information storage means based on the MAC address to identify the IP address. Resolution result providing means that notifies the device that sent the destination resolution request of the IP address identified by the name resolution means, A proxy response device characterized by comprising:

2. A proxy response device according to claim 1, The address information collection means is capable of receiving acknowledgment requests for IPv4 (Internet Protocol Version 4) and IPv6 (Internet Protocol Version 6). The name resolution means can identify both the IPv4 IP address and the IPv6 IP address if they are associated with the identified MAC address. The resolution result providing means, when the name resolution means identifies the IP address for IPv4 and the IP address for IPv6, notifies the device that sent the destination resolution request of both addresses. A proxy response device characterized by the following features.

3. A proxy response method used in a proxy response device provided for a LAN (Local Area Network) to which multiple devices configured with IP (Internet Protocol) addresses are connected, The proxy response device includes a device information storage means that stores and maintains, for each of the multiple devices, an arbitrarily set hostname and the MAC (Media Access Control) address of the device in association. When a confirmation request is received from each of the multiple aforementioned devices to check for duplicate IP addresses, the IP address and MAC address of the device included in the confirmation request are associated and recorded in the address information storage means; When a destination resolution request including a hostname is received from the device connected to the LAN, a name resolution step is performed in which the MAC address is identified by referring to the device information storage means based on the hostname, and the IP address is identified by referring to the address information storage means based on the MAC address. A resolution result provision step which notifies the device that sent the destination resolution request of the IP address identified in the name resolution step, A proxy response method characterized by having the following features.

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