JP2018006891A - Ip address resolution method of relay device, relay device, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IP address resolution method of a relay device, the relay device, and a program that allow a terminal device to more easily obtain an IP address of the relay device on a communication path.SOLUTION: In a network 1 including a PC 200, a wireless AP 100 connected at an upper-level side with the PC 200 via radio L1, and an HGW 400 connected at an upper-level side with the wireless AP 100 via a cable L2, an IP address resolution method of the wireless AP 100 includes the wireless AP 100 snooping into a DNS query transmitted by the PC 200, and transmitting an IP address corresponding to a domain name of the wireless AP 100 to the PC 200 if the DNS query obtained by snooping is a DNS query designating the domain name of the wireless AP 100.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a relay device IP address resolution method, a relay device, and a program.

  In general, a device connected to the Internet is assigned an IP address from a DHCP server in accordance with DHCP (Dynamic Host Configuration Protocol). Since the IP address is difficult for the user to understand, a domain name or a host name is assigned to the device in advance. Further, the IP address and domain name or host name of the apparatus are managed by a DNS (Domain Name System) server. And a user acquires the IP address of the apparatus which wants to access using a domain name or a host name from a DNS server.

  In addition, with the spread of the Internet, a LAN (Local Area Network) has been established in a general household or company. Further, an HGW (Home Gate Way) that connects the LAN and the Internet (WAN; Wide Area Network) has been developed. In addition, wireless LANs that connect the LANs wirelessly are also widely used. A wireless AP (Access Point) is connected to the wireless LAN, and a terminal device such as a PC (Personal Computer) connected to the wireless LAN is generally connected to the HGW via the wireless AP. An IP address is assigned to the HGW, wireless AP, and terminal device.

  The IP address includes a global IP address and a private IP address (local IP address). The global IP address is an IP address assigned from a DHCP server in accordance with DHCP. On the other hand, a private IP address is an IP address assigned to a terminal device such as a PC connected to a lower level of a router or HGW by a router or an HGW having a router function in a LAN. The global IP address is managed by, for example, a DNS server, and the private IP address is managed by, for example, a router or HGW.

  The IP address includes a dynamic IP address that is changed at a predetermined timing and a fixed IP address that is not changed. For this reason, when the IP address is a dynamic IP address, it is necessary to manage a dynamically changed IP address and a domain name or host name by a DNS server or the like.

  For example, in Patent Document 1, in a communication network including a communication terminal whose IP address changes each time the communication network is accessed, the host name and IP address of the communication terminal each time the communication terminal accesses the communication network. Are registered in the DNS server for dynamic IP.

  Patent Document 2 discloses a first terminal, a second terminal connected via a first network, and a gateway connected between the first network and the second network. In the network system including the gateway, the gateway generates a network address of the first terminal, manages the network address in association with the domain name, and receives a request for resolving the domain name of the first terminal from the second terminal. In this case, it is described that a network address corresponding to the domain name is returned to the second terminal.

JP 2000-341325 A JP 2008-060647 A

  By the way, a wireless router used in a LAN constructed in a general home or company has not only a router function but also a wireless access point (wireless AP) function. The wireless router (hereinafter referred to as “wireless AP”) is connected to the HGW connecting the LAN and the Internet (WAN) via a wired LAN. A terminal device such as a PC is connected to the Internet via the wireless AP by belonging to the wireless AP. In general, there are wireless APs that operate as a bridge and those that operate as a router. Then, depending on the environment and use case in which the user uses the terminal device, it is determined which wireless AP to use, which is a wireless AP that operates as a bridge or a wireless AP that operates as a router.

  Further, the user accesses a GUI (Graphical User Interface) using an Internet browser, and changes settings such as an SSID (Service Set Identifier) and an encryption key of the wireless LAN. In order for the user to access the GUI, it is necessary to know the IP address of the wireless AP.

  When the wireless AP operates as a router, the wireless AP or HGW often performs NAT (Network Address Translation). Therefore, a terminal device such as a PC belonging to a wireless AP has a default route as a default AP. Therefore, if the access is performed using the IP address that is the default route, it is possible to access the GUI of the wireless AP.

  On the other hand, when the wireless AP operates as a bridge, the wireless AP may acquire an IP address by a DHCP client function. This is because, when the IP address of the wireless AP is a fixed IP address, the address bandwidth of the terminal device differs depending on the environment in which the user uses the terminal device, so the IP address of the wireless AP and the terminal device used by the user are different. This is because there is a possibility that the address band does not match or the IP address of the wireless AP and the other terminal device have overlapping address bands. The trouble can be prevented if the wireless AP dynamically acquires the IP address by the DHCP client function.

  However, when the wireless AP dynamically acquires an IP address by the DHCP client function, the IP address assigned to the wireless AP only knows the DHCP server. Therefore, it is difficult for the user to know the IP address of the wireless AP. For this reason, the user does not know which IP address can access the GUI of the wireless AP.

  In general, IP addresses are resolved according to DNS. On the other hand, the wireless AP transfers the DNS query as it is to a higher-level device such as an HGW without proxying or snooping the DNS query (DNS Query) transmitted from the terminal device. Therefore, when a DNS query specifying a wireless AP domain name or host name is transmitted from a terminal device, a host device such as an HGW needs to answer the IP address of the wireless AP. However, the HGW does not have a means for determining whether or not a terminal connected to the lower level is a wireless AP, and does not have a DNS answer function for replying the IP address of the wireless AP. Therefore, even if the user uses DNS, it is difficult to know the IP address of the wireless AP.

  An object of the present invention is to provide a relay device IP address resolution method, a relay device, and a program that allow a terminal device to more easily acquire the IP address of the relay device on a communication path.

  An IP address resolution method for a relay device according to a first aspect of the present invention includes: a terminal device; a relay device connected to the host device via a communication path; and a relay device connected to the relay device and the communication path. The relay device snoops the DNS query transmitted from the terminal device, and the DNS query in which the snooping DNS query specifies the domain name of the relay device. In this case, an IP address corresponding to the domain name of the relay device is transmitted to the terminal device.

  A relay device according to a second aspect of the present invention is a relay device that is connected to a higher-level side via a communication path with a terminal device, and is connected to a higher-level device via the communication path, the terminal device Snooping means for snooping the DNS query transmitted from the network, and when the DNS query snooped by the snooping means is a DNS query specifying the domain name of the relay apparatus, an IP address corresponding to the domain name of the relay apparatus is DNS resolver means for transmitting to the terminal device.

  A program according to a third aspect of the present invention is a program that is connected to a higher-order side through a communication path with a terminal device, and is executed by a relay apparatus that is connected to the higher-level apparatus through the communication path. A snooping process for snooping the DNS query transmitted from the terminal apparatus to the relay apparatus, and the DNS query snooping by the snooping process is a DNS query designating a domain name of the relay apparatus. And DNS resolver processing for transmitting an IP address corresponding to the domain name to the terminal device.

  It is possible to provide a relay device IP address resolution method, a relay device, and a program that allow the terminal device to more easily acquire the IP address of the relay device on the communication path.

1 is a block diagram showing a schematic configuration of a network according to Embodiment 1. FIG. 1 is a block diagram showing a network according to Embodiment 1. FIG. 2 is a block diagram showing a configuration of a wireless access point (wireless AP) according to Embodiment 1. FIG. It is a figure which shows the sequence from which wireless AP and PC which concern on Embodiment 1 acquire an IP address. It is a figure which shows the sequence at the time of PC which concerns on Embodiment 1 accesses the internet. It is a figure which shows the sequence at the time of PC which concerns on Embodiment 1 accessing GUI. It is a figure which shows the sequence at the time of PC which concerns on Embodiment 2 accessing GUI.

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a network 1 according to Embodiment 1 of the present invention. As shown in FIG. 1, a wireless access point (AP: Access Point) 100 as a relay apparatus according to Embodiment 1 of the present invention includes a DNS snooping unit 104A as a snooping unit, and a DNS resolver unit 104B as a DNS resolver unit. Etc.

  A wireless access point (hereinafter simply referred to as “wireless AP”) 100 is a personal computer (hereinafter simply referred to as “PC”) 200 as a terminal device and wireless (WLAN; Wireless LAN) as a communication path. It is connected to the upper side by L1. Further, it is connected to an HGW (Home Gate Way) 400 as a host device by a wired L2 as a communication path.

  Then, the DNS snooping unit 104A of the wireless AP 100 snoops the DNS query transmitted from the PC 200. Further, the DNS resolver unit 104B of the wireless AP 100 transmits an IP address corresponding to the domain name of the wireless AP 100 to the PC 200 when the DNS query snooping by the DNS snooping unit 104A is a DNS query specifying the domain name of the wireless AP 100. To do. Note that the IP address used in the first embodiment is, for example, an IPv4 address.

  The network 1 according to the first embodiment will be described in more detail with reference to FIG. FIG. 2 is a block diagram showing the network 1 according to the first embodiment. As illustrated in FIG. 2, the network 1 includes a wireless AP 100 as a relay device, PCs 200 and 300 as terminal devices, an HGW 400 as a host device, and the like.

  The wireless AP 100 and the PC 200 are connected by the wireless L1. Then, for example, wireless communication is performed based on a wireless communication standard defined by IEEE 802.11. Further, the HGW 400 and the wireless AP 100 are connected by a cable L2. Further, the PC 300 and the HGW 400 are connected by a wired L3.

As shown in FIG. 2, the HGW 400 connects a local area network (LAN) 11 including the wireless AP 100, the PCs 200 and 300, the wireless L 1, the wires L 2 and L 3, and the external Internet 12.
Specifically, the PC 200 transmits a DNS query to the HGW 400 via the wireless AP 100. The HGW 400 transmits an IP address corresponding to the DNS of the DNS query to the PC 200 via the wireless AP 100. Then, the PC 200 accesses a device such as a server on the Internet 12 using the IP address.
Further, the PC 300 transmits a DNS query to the HGW 400. The HGW 400 transmits an IP address corresponding to the DNS of the DNS query to the PC 300. Then, the PC 300 accesses a device such as a server on the Internet 12 using the IP address.

  As shown in FIG. 3, the wireless AP 100 includes a wireless AP unit 101, a DHCP client unit 102, an HTTP server unit 103, a proxy DNS unit 104, a filter unit 105 as a filtering unit, a WLAN interface 106, a LAN interface 107, and the like. The wireless AP 100 is connected to the PC 200 via the WLAN interface 106. The wireless AP 100 is connected to the HGW 400 via the LAN interface 107. The proxy DNS unit 104 includes a DNS snooping unit 104A as a snooping unit, a DNS resolver unit 104B as a DNS resolver unit, a DNS record generation unit 104C, a DNS cache unit 104D, and the like.

The wireless AP 100 includes a CPU (not shown) and a storage unit (not shown). Then, when the CPU executes a program stored in the storage unit, processing in the wireless AP 100 is realized.
Further, the program stored in the storage unit of the wireless AP 100 includes a code for realizing processing of the wireless AP 100 by being executed by the CPU. Note that the storage unit includes, for example, an arbitrary storage device that can store this program and various types of information used for processing in the wireless AP 100. The storage device is, for example, a memory.

  Specifically, the CPU executes a program stored in the storage unit, thereby causing the wireless AP unit 101, the DHCP client unit 102, the HTTP server unit 103, the proxy DNS unit 104, the filter unit 105, the WLAN interface 106, The function of each unit of the wireless AP 100 such as the LAN interface 107 is realized. That is, all the various control processes performed by the wireless AP 100 are realized by an implementation unit in which the CPU and the program stored in the storage unit cooperate.

  The wireless AP unit 101 controls wireless communication between the wireless AP 100 and the PC 200. Specifically, the wireless AP unit 101 controls wireless communication based on a wireless communication standard defined by IEEE 802.11 or the like.

  The DHCP client unit 102 acquires the IP address (for example, 192.0.2.2) of the wireless AP 100 from the HGW 400 according to DHCP.

  The HTTP server unit 103 transmits information such as HTML and objects to a lower level connected device in accordance with HTTP. In the first embodiment, in particular, the HTTP server unit 103 includes an FQDN (Full Query Domain Name) for accessing the IP address and GUI of the wireless AP 100, for example, ap. Access to the GUI is permitted to a terminal such as the PC 200 that has accessed by specifying the test. As a result, a terminal such as the PC 200 accessing the GUI can change settings such as the SSID and encryption key for wireless communication.

  The proxy DNS unit 104 performs a proxy for a specific DNS query, for example, a DNS query that specifies the domain name of the wireless AP 100. Specifically, the proxy DNS unit 104 includes a DNS snooping unit 104A, a DNS resolver unit 104B, a DNS record generation unit 104C, a DNS cache unit 104D, and the like. Note that the wireless AP 100 is an FQDN for accessing the GUI of the wireless AP 100, ap. test as a domain name.

  DNS snooping unit 104A snoops the DNS query transmitted from PC 200. Also, the DNS snooping unit 104A determines that the snooping DNS query is the domain name of the wireless AP 100, ap. If the DNS query specifies “test”, the fact is notified to the DNS resolver unit 104B. Specifically, the DNS snooping unit 104A determines whether or not the snooped DNS query is a DNS query that specifies the domain name of the wireless AP 100. When the DNS query that has been snooped is a DNS query that specifies the domain name of the wireless AP 100, the DNS resolver unit 104B is notified of this fact.

  When the snooped DNS query is a DNS query specifying the domain name of the wireless AP 100, the DNS resolver unit 104B transmits an IP address corresponding to the domain name of the wireless AP 100 to the PC 200. Specifically, when the snooping DNS query is a DNS query specifying the domain name of the wireless AP 100, the DNS resolver unit 104B displays a DNS record corresponding to an IP address corresponding to the domain name of the wireless AP 100, which will be described later. Extracted from the cache unit 104D, generates a DNS Answer message from the DNS record, and transmits the DNS Answer to the PC 200. Also, when the DNS resolver unit 104B transmits the DNS Answer to the PC 200, the IP address of the HGW 400 is used as the source IP address.

  The DNS record generation unit 104C generates a DNS record that combines the IP address of the wireless AP 100 acquired by the DHCP client unit 102 and the FQDN for accessing the GUI, and stores the DNS record in the DNS cache unit 104D. Here, the FQDN for accessing the GUI is the domain name of the wireless AP 100, ap. test.

  The DNS cache unit 104D includes a domain name of the wireless AP 100, ap. The test and the IP address of the wireless AP 100, 192.0.2.2, are stored in association with each other. Specifically, the DNS cache unit 104D stores a DNS record that is a combination of the IP address of the wireless AP 100 generated by the DNS record generating unit 104C and the FQDN (domain name of the wireless AP 100) for accessing the GUI. doing.

  When the DNS query snooping by the DNS snooping unit 104 </ b> A is a DNS query specifying the domain name of the wireless AP 100, the filter unit 105 discards the DNS query and does not transmit the DNS query to the HGW 400. Specifically, the filter unit 105 is a packet filter and discards a packet. More specifically, the filter unit 105 determines whether or not the snooped DNS query is a DNS query that specifies the domain name of the wireless AP 100. When the snooped DNS query is a DNS query specifying the domain name of the wireless AP 100, the filter unit 105 discards the DNS and does not transmit the DNS query to the HGW 400. On the other hand, when the snooped DNS query is not a DNS query specifying the domain name of the wireless AP 100, the filter unit 105 transmits the DNS query to the HGW 400 as it is.

  As shown in FIG. 2, the HGW 400 includes a DHCP server unit 401, a proxy DNS unit 402, and the like.

  The DHCP server unit 401 assigns an IP address to the wireless AP 100, PC 200, and PC 300 connected to the LAN 11 side of the HGW 400. Here, the IP address and bandwidth on the LAN 11 side of the HGW 400 is, for example, 192.0.2.1/24. Note that the WAN (Wide Area Network) side of the HGW 400 is connected to the Internet 12 and can communicate.

  The proxy DNS unit 402 has a general proxy function. Specifically, the proxy DNS unit 402 has a server function and a client function. More specifically, when the HGW 400 receives a DNS query from the PC 200 via the wireless AP 100, the proxy DNS unit 402 transmits an IP address corresponding to the DNS query to the PC 200 via the wireless AP 100. Similarly, when the HGW 400 receives a DNS query from the PC 300, the proxy DNS unit 402 transmits an IP address corresponding to the DNS query to the PC 300.

  Next, a sequence in which the wireless AP 100 and the PC 200 according to the first embodiment obtain an IP address will be described with reference to FIG.

First, a sequence (DHCP05) in which the wireless AP 100 acquires an IP address will be described.
The DHCP client unit 102 of the wireless AP 100 transmits a Discover message to the HGW 400 (step S1). Next, the DHCP server unit 401 of the HGW 400 transmits an Offer message to the wireless AP 100 in response to the received Discover message (Step S2).

  Next, the DHCP client unit 102 of the wireless AP 100 transmits a Request message to the HGW 400 (Step S3). Next, the DHCP server unit 401 of the HGW 400 transmits an Ack message including an IP address to the wireless AP 100 in response to the received Request message (Step S4). Here, it is assumed that the IP address acquired by the wireless AP 100 is 192.0.2.2. Further, this IP address becomes the GUI address of the wireless AP 100.

  Here, in step S4, the DNS record generating unit 104C determines the IP address of the wireless AP 100 acquired by the wireless AP 100 and the FQDN for accessing the GUI, for example, ap. A DNS record that combines test and is generated and stored in the DNS cache unit 104D.

  In the sequence DHCP05, the wireless AP 100 has acquired an IP address by the DHCP client function of the wireless AP 100 (the function of the DHCP client unit 102), so there is no need to bridge and the PC 200 connected to the wireless L1 side. Do not forward packets to For this reason, the PC 200 cannot know the IP address of the wireless AP 100.

Next, a sequence (DHCP06) in which the PC 200 acquires an IP address will be described.
The PC 200 transmits a Discover message to the HGW 400 via the wireless AP 100 (step S5). Here, since the wireless AP 100 is a bridge, communication between the PC 200 and the HGW 400 is basically performed without the wireless AP 100 being involved. Next, the DHCP server unit 401 of the HGW 400 transmits an Offer message to the PC 200 via the wireless AP 100 in response to the received Discover message (Step S6).

  Next, the PC 200 transmits a Request message to the HGW 400 via the wireless AP 100 (step S7). Next, the DHCP server unit 401 of the HGW 400 transmits an Ack message including an IP address to the PC 200 via the wireless AP 100 in response to the received Request message (Step S8). Here, it is assumed that the IP address acquired by the PC 200 is 192.0.2.3.

  Next, a sequence when the PC 200 according to the first embodiment accesses the Internet 12 will be described with reference to FIG. Here, the PC 200 is connected to the example. com will be described.

  First, the PC 200 uses example. com is transmitted to the HGW 400 via the wireless AP 100 (step S101). Here, the DNS snooping unit 104A of the wireless AP 100 snoops the DNS query transmitted from the PC 200. Next, the DNS snooping unit 104A of the wireless AP 100 determines whether or not the snooped DNS query is a DNS query that specifies the domain name of the wireless AP 100. Here, since the DNS query that was snooped is not a DNS query that specifies the domain name of the wireless AP 100, the DNS snooping unit 104A does not notify the DNS resolver unit 104B. For this reason, the DNS resolver unit 104B does not perform any processing, and the DNS query is transmitted to the filter unit 105. Next, the filter unit 105 of the wireless AP 100 determines whether or not the snooped DNS query is a DNS query that specifies the domain name of the wireless AP 100. Here, since the snooped DNS query is not a DNS query specifying the domain name of the wireless AP 100, the filter unit 105 transmits the DNS query to the HGW 400 as it is.

  Next, the proxy DNS unit 402 of the HGW 400 uses example. com is transmitted to a DNS server (not shown) on the Internet 12 (step S102).

  Next, the HGW 400 receives a domain name “example. com, for example, 203.0.113.1 is received (step S103). Next, the HGW 400 reads the domain name example. com is transmitted to the PC 200 through the wireless AP 100 (step S104).

  Next, the PC 200 uses the IP address 203.00.113. com (step S105).

Next, a sequence when the PC 200 according to the first embodiment accesses the GUI will be described with reference to FIG.
First, as a domain name, the PC 200 sets the domain name of the wireless AP 100 (FQDN for accessing the GUI) ap. A DNS query specifying a test is transmitted to the HGW 400 via the wireless AP 100 (step S201).

  Here, the DNS snooping unit 104A of the wireless AP 100 snoops the DNS query transmitted from the PC 200. Next, the DNS snooping unit 104A of the wireless AP 100 determines whether or not the snooped DNS query is a DNS query that specifies the domain name of the wireless AP 100. Here, since the snooped DNS query is a DNS query that specifies the domain name of the wireless AP 100, the DNS snooping unit 104A notifies the DNS resolver unit 104B of the fact.

  Next, the DNS resolver unit 104B extracts a DNS record corresponding to the domain name of the wireless AP 100 from the DNS cache unit 104D, generates a DNS Answer message from the DNS record, and transmits the DNS Answer to the PC 200 (step S202). . Note that when the DNS resolver unit 104B transmits the DNS Answer to the PC 200, the IP address of the HGW 400 is used as the source IP address.

  Here, the DNS query is transmitted to the filter unit 105. Next, the filter unit 105 of the wireless AP 100 determines whether or not the snooped DNS query is a DNS query that specifies the domain name of the wireless AP 100. Here, since the snooped DNS query is a DNS query specifying the domain name of the wireless AP 100, the filter unit 105 discards the DNS query and does not transmit it to the HGW 400.

  Next, the PC 200 accesses the GUI of the wireless AP 100 using the IP address of the wireless AP 100 transmitted in step S202, 192.0.2.2 (step S203).

  In the IP address resolution method, wireless AP 100, and program according to Embodiment 1 described above, DNS snooping unit 104A snoops the DNS query transmitted from PC 200, and is snooped by DNS snooping unit 104A. When the DNS query is a DNS query specifying the domain name of the wireless AP 100, the DNS resolver unit 104B transmits a DNS Answer including the IP address corresponding to the domain name of the wireless AP 100 to the PC 200. Therefore, it is possible to provide an IP address resolution method, a wireless AP 100, and a program for the wireless AP 100 that allow the PC 200 to easily acquire the IP address of the wireless AP 100 on the communication path.

  In addition, when the snooped DNS query is a DNS query specifying the domain name of the wireless AP 100, the filter unit 105 discards the DNS query and does not transmit it to the HGW 400. If the DNS query is not discarded by the filter unit 105, the query is transmitted to a DNS server on the Internet 12, and a response to the DNS query is transmitted from the DNS server to the PC 200 via the wireless AP 100. However, since the HGW 400 has assigned an IP address to the wireless AP, the DNS server does not know the IP address of the wireless AP 100. Therefore, the answer is not the IP address of the wireless AP 100. Then, the PC 200 receives two answers, a DNS Answer from the wireless AP 100 and a reply from the DNS server. However, in the first embodiment, since the DNS query is discarded by the filter unit 105, the PC 200 receives only the DNS Answer from the wireless AP 100, and the PC 200 surely acquires the IP address of the wireless AP 100. be able to.

  Further, when the DNS query snooping by the DNS snooping unit 104A is not a DNS query specifying the domain name of the wireless AP 100, the filter unit 105 transmits the DNS query to the HGW 400 as it is. Therefore, a DNS query other than the DNS query that specifies the domain name of the wireless AP 100 is appropriately transmitted to the DNS server on the Internet 12.

  Further, when the DNS resolver unit 104B transmits an IP address corresponding to the domain name of the wireless AP 100 to the PC 200, the IP address of the HGW 400 is used as the IP address of the transmission source. Therefore, the PC 200 can receive a reply from the same IP address of the transmission source as the exchange of DNS query inquiries with the conventional HGW 400. Thereby, it is possible to avoid the connectivity problem that the PC 200 cannot receive the answer due to the different IP addresses of the transmission sources.

  Also, the DNS resolver unit 104B transmits to the PC 200 a DNS Answer generated from a DNS record that combines the IP address of the wireless AP 100 and the domain name (FQDN for accessing the GUI). Therefore, the PC 200 can acquire the IP address of the wireless AP 100 regardless of the method for acquiring the IP address of the wireless AP 100 and the type of Internet protocol such as IPv4 or IPv6. For example, when the Internet protocol is IPv6, there are a plurality of methods for acquiring an IPv6 address, such as stateless and stateful. However, in the first embodiment, when the IPv6 address of the wireless AP 100 is determined, the DNS resolver unit 104B transmits the DNS Answer including the IPv6 and the domain name to the PC 200. Therefore, the method for acquiring the IP address of the wireless AP 100 and the Internet Regardless of the protocol, the PC 200 can acquire the IP address of the wireless AP 100.

  Also, when the DHCP client unit 102 acquires the IP address of the wireless AP 100, the DNS record generating unit 104C combines the IP address of the wireless AP 100 and the domain name (FQDN for accessing the GUI) of the wireless AP 100. A record is generated and stored in the DNS cache unit 104D. Therefore, even when the IP address of the wireless AP 100 is changed, when the DHCP client unit 102 acquires the IP address of the changed wireless AP 100, the DNS record generating unit 104C causes the changed IP address and the wireless AP 100 to A DNS record that is combined with the domain name is newly generated and stored in the DNS cache unit 104D. Therefore, even if the IP address of the wireless AP 100 is changed, the proxy DNS unit 104 of the wireless AP 100 can transmit the changed IP address to the PC 200. In other words, the proxy DNS unit 104 can dynamically follow the IP address of the wireless AP 100.

Embodiment 2
Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 7 shows a sequence when the PC 200 according to the second embodiment of the present invention accesses the GUI. As shown in FIG. 7, the network 2 according to the second embodiment includes an Ether converter (wireless slave unit) 500 and a wireless relay device 600 instead of the wireless AP 100 as a relay device, and instead of the PC 200 as a terminal device. In addition, the point provided with the PC 700 is different from the network 1 according to the first embodiment. Accordingly, the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 7, the Ether converter 500 and the PC 700 are connected by a wired L4. The Ether converter 500 and the wireless relay device 600 are connected by a wireless L5. Further, the wireless relay device 600 and the HGW 400 are connected by the wireless L6.

  Then, as shown in FIG. 7, the HGW 400 couples a local area network (LAN) 21 including a PC 700, an Ether converter 500, a wireless relay device 600, a wired L 4, a wireless L 5, L 6, and the like and the external Internet 12. .

  In addition to the function as a normal wireless slave device, the Ether converter 500 includes a DHCP client unit 102, an HTTP server unit 103, a proxy DNS unit 104, and a filter unit 105, as in the wireless AP 100 according to the first embodiment. It has a configuration. Similarly, the wireless relay device 600 has a DHCP client unit 102, an HTTP server unit 103, a proxy DNS unit 104, a filter unit, in addition to the function as a normal wireless relay device, similarly to the wireless AP 100 according to the first embodiment. 105 configurations are provided.

The FQDN for accessing the GUI of the Ether converter 500 is cnv. The IP address of the Ether converter 500 is 192.0.2.6.
Further, the FQDN for accessing the GUI of the wireless relay device 600 is rep. The IP address of the Ether converter 500 is 192.0.2.5.
The IP address of the PC 700 is 192.0.2.7.

First, a sequence in which the PC 700 accesses the GUI of the Ether converter 500 will be described.
As illustrated in FIG. 7, the PC 700 uses cnv. As the domain name, which is the domain name of the Ether converter 500 (FQDN for accessing the GUI). A DNS query designating the test is transmitted to the HGW 400 via the Ether converter 500 (step S301).

  Here, the DNS snooping unit of the Ether converter 500 snoops the DNS query transmitted from the PC 700. Next, the DNS snooping unit of the Ether converter 500 determines whether or not the snooped DNS query is a DNS query that specifies the domain name of the Ether converter 500. Here, since the snooping DNS query is a DNS query specifying the domain name of the Ether converter 500, the DNS snooping unit notifies the DNS resolver unit of the Ether converter 500 to that effect.

  Next, the DNS resolver unit extracts a DNS record corresponding to the domain name of the Ether converter 500 from the DNS cache unit, generates a DNS Answer message from the DNS record, and transmits the DNS Answer to the PC 700 (step S302). Note that the DNS resolver unit uses the IP address of the HGW 400 as the source IP address when transmitting the DNS Answer to the PC 700.

  Also, here, the DNS query is transmitted to the filter unit of the Ether converter 500. Next, the filter unit of the Ether converter 500 determines whether the snooped DNS query is a DNS query that specifies the domain name of the Ether converter 500. Here, since the snooped DNS query is a DNS query specifying the domain name of the Ether converter 500, the filter unit discards the DNS query and does not transmit it to the HGW 400.

  Next, the PC 700 accesses the GUI of the Ether converter 500 using the IP address 192.0.2.6 of the Ether converter 500 transmitted in Step S302 (Step S303).

Next, a sequence in which the PC 700 accesses the GUI of the wireless relay device 600 will be described.
As illustrated in FIG. 7, the PC 700 uses a domain name “rep. Rep.” That is the domain name of the wireless relay device 600 (FQDN for accessing the GUI). A DNS query designating a test is transmitted to the HGW 400 via the wireless relay device 600 (step S304).

  Here, the DNS snooping unit of the wireless relay device 600 snoops the DNS query transmitted from the PC 700. Next, the DNS snooping unit of the wireless relay device 600 determines whether or not the snooped DNS query is a DNS query that specifies the domain name of the wireless relay device 600. Here, since the snooping DNS query is a DNS query specifying the domain name of the radio relay device 600, the DNS snooping unit notifies the DNS resolver unit of the radio relay device 600 to that effect.

  Next, the DNS resolver unit extracts a DNS record corresponding to the domain name of the radio relay device 600 from the DNS cache unit, generates a DNS Answer message from the DNS record, and transmits the DNS Answer to the PC 700 (step S305). . Note that the DNS resolver unit uses the IP address of the HGW 400 as the source IP address when transmitting the DNS Answer to the PC 700.

  In addition, here, the DNS query is transmitted to the filter unit of the wireless relay device 600. Next, the filter unit of the wireless relay device 600 determines whether the snooped DNS query is a DNS query that specifies the domain name of the wireless relay device 600. Here, since the snooped DNS query is a DNS query specifying the domain name of the radio relay device 600, the filter unit discards the DNS query and does not transmit it to the HGW 400.

  Next, the PC 700 accesses the GUI of the wireless relay device 600 using the IP address 192.0.2.5 of the wireless relay device 600 transmitted in step S302 (step S306).

  In the above-described Ether converter 500 and wireless relay device 600 IP address solving method, wireless AP 100, and program according to the second embodiment, the wireless AP 100 IP address solving method, wireless AP 100, And the effect similar to a program can be acquired.

Embodiment 3 FIG.
Next, Embodiment 3 will be described. The third embodiment is different from the first embodiment in that IPv6 is used as the Internet protocol. Accordingly, the same components are denoted by the same reference numerals and description thereof is omitted. Specifically, an A record is used for an IPv4 address, whereas an AAAA (quad) record is used for an IPv6 address.

  Further, the DHCP client unit 102 acquires the IPv6 address of the wireless AP 100 from the HGW 400 according to DHCP.

  In addition, the DNS record generation unit 104C generates a DNS record that combines the IPv6 address and AAAA record of the wireless AP 100 acquired by the DHCP client unit 102 and the FQDN for accessing the GUI, and stores the DNS record in the DNS cache unit 104D. .

  Also, the DNS cache unit 104D stores a domain name (FQDN for accessing the GUI) of the wireless AP 100, an IP address of the wireless AP 100, and an AAAA record in association with each other. Specifically, the DNS cache unit 104D stores the DNS record generated by the DNS record generation unit 104C.

  The other processes in the third embodiment are the same as those in the first embodiment, and thus description thereof is omitted.

  The wireless AP 100 IP address resolution method, wireless AP 100, and program according to Embodiment 3 described above are the same as the wireless AP 100 IP address resolution method, wireless AP 100, and program according to Embodiment 1. An effect can be obtained. That is, the present invention can provide the same effect regardless of whether the Internet protocol is IPv4 or IPv6.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, the IP addresses of the wireless AP 100, the Ether converter 500, and the wireless relay device 600 are not dynamically acquired according to DHCP, but may be fixed IP addresses. When the IP addresses of the wireless AP 100, the Ether converter 500, and the wireless relay device 600 are fixed IP addresses, the DNS record generation unit 104C uses the fixed IP address acquired by the DHCP client unit 102 and the FQDN (wireless access to the GUI). A DNS record combining the AP 100, the Ether converter 500, and the domain name of the wireless relay device 600 may be generated and stored in the DNS cache unit 104D.

In the above embodiment, a relay device provided in the LAN 11 in a home environment such as a general home or a company is assumed, but the present invention is not limited to this. That is, if there is a relay device having functions of the snooping means, DNS resolver means, filter means, etc. of the present invention on a communication path other than the network in the home environment, the terminal device may be connected to the relay device in the same manner. Is possible.
"Appendix 1"
In a network comprising a terminal device, a relay device connected to the host device via a communication path, and a host device connected to the relay device and the host device via the communication path,
The relay device snoops a DNS query transmitted from the terminal device, and when the snooped DNS query is a DNS query specifying a domain name of the relay device, an IP address corresponding to the domain name of the relay device is set. An IP address resolution method for a relay device, which is transmitted to the terminal device.
"Appendix 2"
The relay device according to appendix 1, wherein the relay device discards the DNS query and does not transmit the DNS query to the higher-level device when the snooping DNS query is a DNS query specifying a domain name of the relay device. Device IP address resolution method.
"Appendix 3"
The relay device according to appendix 1 or 2, wherein the relay device transmits the DNS query as it is to the host device when the snooped DNS query is not a DNS query specifying the domain name of the relay device. Solution.
"Appendix 4"
The relay device is a DNS query in which the snooping DNS query specifies a domain name of the relay device, and when transmitting an IP address corresponding to the domain name of the relay device to the terminal device, a source IP address The IP address resolution method for a relay device according to any one of appendices 1 to 3, wherein the IP address of the host device is used as
"Appendix 5"
A relay device connected to a host device via a communication path and a host device, and connected to a host device via the communication path,
Snooping means for snooping a DNS query transmitted from the terminal device;
If the DNS query snooping by the snooping means is a DNS query that specifies the domain name of the relay device, DNS resolver means for transmitting an IP address corresponding to the domain name of the relay device to the terminal device;
A relay device comprising:
"Appendix 6"
Appendix 5 comprises filter means for discarding the DNS query and not sending the DNS query to the host device when the DNS query snooping by the snooping means is a DNS query specifying the domain name of the relay device The relay device described.
"Appendix 7"
7. The relay device according to appendix 6, wherein when the DNS query snooped by the snooping unit is not a DNS query specifying a domain name of the relay device, the filter unit transmits the DNS query to the host device as it is.
"Appendix 8"
The DNS resolver means uses the IP address of the host device as the source IP address when transmitting the IP address corresponding to the domain name of the relay device to the terminal device. The relay device described in 1.
"Appendix 9"
A program that is connected to a host device via a communication path and is executed by a relay device that is connected to the host device via the communication path,
In the relay device,
A snooping process for snooping a DNS query transmitted from the terminal device;
When the DNS query snooping by the snooping process is a DNS query that specifies the domain name of the relay device, a DNS resolver process that transmits an IP address corresponding to the domain name of the relay device to the terminal device;
A program that executes
"Appendix 10"
In the relay device,
Appendix 9 When the DNS query snooping by the snooping process is a DNS query that specifies the domain name of the relay device, the DNS query is discarded, and a filtering process that does not transmit the DNS query to the host device is executed. The program described in.
"Appendix 11"
In the relay device,
The program according to appendix 9 or 10, wherein when the DNS query snooping by the snooping process is not a DNS query specifying a domain name of the relay apparatus, a process of transmitting the DNS query to the host apparatus as it is is executed.
"Appendix 12"
In the relay device,
Any one of appendices 9 to 11, wherein in the DNS resolver process, when an IP address corresponding to the domain name of the relay device is transmitted to the terminal device, the IP address of the host device is used as the source IP address. The program described in the section.

1 Network 11 LAN
12 Internet 2 Network 21 LAN
100 wireless AP (relay device)
101 Wireless AP unit 102 DHCP client unit 103 HTTP server unit 104 Proxy DNS unit 104
104A DNS snooping part (snooping means)
104B DNS resolver unit (DNS resolver means)
104C DNS record generation unit 104D DNS cache unit 105 Filter unit 106 WLAN interface 107 LAN interface 200 PC (terminal device)
400 HGW (host device)
401 DHCP server unit 402 Proxy DNS unit 500 Ether converter (relay device)
600 Wireless repeater (relay device)
700 PC (terminal equipment)
L1, L5, L6 Wireless L2, L3, L4 Wired

Claims (10)

In a network comprising a terminal device, a relay device connected to the host device via a communication path, and a host device connected to the relay device and the host device via the communication path,
The relay device snoops a DNS query transmitted from the terminal device, and when the snooped DNS query is a DNS query specifying a domain name of the relay device, an IP address corresponding to the domain name of the relay device is set. An IP address resolution method for a relay device, which is transmitted to the terminal device.   2. The relay device according to claim 1, wherein when the snooped DNS query is a DNS query specifying a domain name of the relay device, the relay device discards the DNS query and does not transmit the DNS query to the host device. Method for resolving IP address of relay device.   3. The relay device IP according to claim 1, wherein, when the snooped DNS query is not a DNS query specifying a domain name of the relay device, the relay device transmits the DNS query to the host device as it is. Address resolution method.   The relay device is a DNS query in which the snooping DNS query specifies a domain name of the relay device, and when transmitting an IP address corresponding to the domain name of the relay device to the terminal device, a source IP address The IP address resolution method for a relay device according to any one of claims 1 to 3, wherein the IP address of the host device is used as A relay device connected to a host device via a communication path and a host device, and connected to a host device via the communication path,
Snooping means for snooping a DNS query transmitted from the terminal device;
If the DNS query snooping by the snooping means is a DNS query that specifies the domain name of the relay device, DNS resolver means for transmitting an IP address corresponding to the domain name of the relay device to the terminal device;
A relay device comprising:   6. When the DNS query snooping by the snooping means is a DNS query specifying a domain name of the relay device, the DNS query is discarded, and filtering means that discards the DNS query and does not transmit the DNS query to the host device is provided. The relay device described in 1.   7. The relay device according to claim 6, wherein when the DNS query snooping by the snooping unit is not a DNS query specifying a domain name of the relay device, the filter unit transmits the DNS query to the host device as it is. .   The DNS resolver means uses the IP address of the host device as a source IP address when transmitting an IP address corresponding to a domain name of the relay device to the terminal device. The relay device according to item. A program that is connected to a host device via a communication path and is executed by a relay device that is connected to the host device via the communication path,
In the relay device,
A snooping process for snooping a DNS query transmitted from the terminal device;
When the DNS query snooping by the snooping process is a DNS query that specifies the domain name of the relay device, a DNS resolver process that transmits an IP address corresponding to the domain name of the relay device to the terminal device;
A program that executes In the relay device,
The DNS query that is snooped by the snooping process is a DNS query that specifies a domain name of the relay device, the DNS query is discarded, and a filtering process that does not transmit the DNS query to the host device is executed. 9. The program according to 9.

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