JP2005033251A - Relaying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relaying apparatus capable of smoothly relaying a communication packet by avoiding the duplication of an address between networks. <P>SOLUTION: A relaying apparatus 9 for relaying data packets between first and second networks includes: a storage means 25 for storing the range of an addresses which is dynamically assigned to apparatuses connected to the second network; a detection means for detecting the address range of the first network; an address duplication discrimination means 26a for discriminating whether the address range detected by the detection means is coincident or in duplicate with the address range stored in the storage means; and an address revision means 26b for revising the address range stored in the storage means 25 in a way of being not in duplicate with the address range detected by the detection means when the address duplicate discrimination means 26a discriminates the presence of the duplication in the address ranges. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a relay device capable of relaying communication packets between networks.
[0002]
[Prior art]
Conventionally, a relay device that relays communication packets between a first network and a second network, such as a router, has a DHCP function, and dynamically assigns an IP address to a subordinate (second network side) terminal. There is something.
[0003]
In such a relay device, the user needs to manually set an address range to be assigned to a terminal under the relay device, and a burden is great for a user who does not have expertise.
[0004]
Thus, although it is conceivable to set an address range to be dynamically allocated to the relay device in advance, there is a possibility that the first network matches or overlaps the set address range. When the address ranges of the first network and the second network match or overlap, there may be a case where the subordinate terminal cannot access the first network. For example, when the same address “192.168.2.1” exists in the first network and the second network, the first network side device “192.168.2.1” is transmitted from the second network side. Even if the user wants to access the network, it is only sent to the second network side and is not transferred to the first network.
[0005]
In addition, such a problem can be avoided by assigning a non-overlapping address range from the higher-level relay device on the first network side (see, for example, Patent Document 1), but the DHCP device has a DHCP address range. If there is no higher order relay device to allocate, the above problem remains.
[0006]
[Patent Document 1]
JP 2002-290437 A
[0007]
[Problems to be solved by the invention]
As described above, when address duplication occurs between the first network side and the second network side, there is a problem that packet routing between the networks does not function well.
[0008]
An object of the present invention is to provide a relay apparatus that can smoothly relay communication packets while avoiding duplication of addresses between networks.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is a relay device that relays data packets between a first network and a second network, and is dynamically connected to a device connected to the second network. Storage means for storing a range of addresses to be assigned to, detection means for detecting the address range of the first network, and whether the address range detected by the detection means and the address range stored in the storage means match or overlap If the address duplication determination means and the address duplication judgment means determine that there is an address range duplication, the address range stored in the storage means overlaps the address range detected by the detection means Address changing means for changing the address so as not to be changed.
[0010]
Thereby, it is possible to smoothly relay communication packets while avoiding duplication of addresses between networks.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
A first invention of the present invention is a relay device that relays data packets between a first network and a second network, and has an address dynamically allocated to a device connected to the second network. A storage unit for storing a range; a detection unit for detecting an address range of the first network; and determining whether an address range detected by the detection unit and an address range stored in the storage unit match or overlap. When the address duplication determination unit and the address duplication judgment unit determine that there is an address range duplication, the address range stored in the storage unit is changed so as not to overlap with the address range detected by the detection unit. And a terminal under control of an address that does not overlap with the address range of the first network. It can be assigned.
[0012]
The second invention of the present invention is the relay according to the first invention, wherein the detecting means detects the address range of the first network based on the address of the own device assigned from the address assigning device of the first network. Since the address range of the first network can be detected by using an address assigned for communication with the first network from an address assigning device such as DHCP, the configuration of the address detecting means is easy. It becomes.
[0013]
A third invention of the present invention is the first or second invention, further comprising setting means for setting an address of the own apparatus based on an input from the input means, wherein the detection means is the first set by the setting means. The relay device detects the address range of the first network based on the address of the first network, and detects the address range of the first network using the address set for communication with the first network. Therefore, the configuration of the address detecting means is facilitated.
[0014]
According to a fourth aspect of the present invention, in the second or third aspect, the detecting means is a relay device that detects the address range of the first network from a subnet mask or CIDR, and the subnet mask indicating the address range of the first network Or CIDR facilitates the configuration of the address detection means.
[0015]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the address that can be accessed to the own device is fixed even when the address of the own device is changed by the address changing means. Second storage means for storing automatically, and an own apparatus response means for returning a predetermined response when an address stored in the second storage means is accessed from the second network, After the address changing unit has changed the address range stored in the storage unit, and there is a transmission packet for the address stored in the second storage unit from the second network side, A relay device that operates the own device response means without transferring to the first network side, and is a range of addresses that are dynamically allocated to devices connected to the second network. There even when it is changed, since there is no change of address for accessing the pre own device, can be avoided that the second network address of the relay apparatus can not know. In particular, when the relay device is set from a device connected to the second network, if the address of the relay device is dynamically changed, the setting itself may become difficult. Problems can be avoided.
[0016]
According to a sixth aspect of the present invention, in any one of the fifth aspects, after the address range stored in the storage unit is changed by the address changing unit, the second storage is performed from the second network side. In response to a transmission packet addressed to the address stored in the means, the source address of the response packet is stored in the second storage means when the self-device response means is operated without being transferred to the network side. When the address is stored in the second storage means and the relay apparatus transmits as an address, the address stored in the storage means is stored in the second storage means without using the address of the own apparatus as the response packet. Therefore, the device that has transmitted the transmission packet from the second network side, the transmission source of the response to the transmission packet is the destination address of the transmission packet. By scan different, there is no such thing as discarded as is not the correct one response packet.
[0017]
According to a seventh invention of the present invention, in any one of the first to fourth inventions, a third storage means for storing a host name and an address corresponding to the host name for accessing the device from the second network side; When an address stored in advance in the third storage means is accessed from the second network, the own device response means for returning a predetermined response, and the host name from the device connected to the second network Receiving a query for an address for the host name received from the device connected to the second network from a device connected to the second network. Then, instead of operating the transfer means, the relay device returns the address stored in the third storage means in response data, Even when the range of addresses dynamically allocated to devices connected to the network is changed, the address of the relay device can be obtained by transmitting a communication packet with a predetermined host name from the device connected to the second network. Can do. In particular, when the relay device is set from a device connected to the second network, if the address of the relay device is dynamically changed, the setting itself may become difficult. Problems can be avoided.
[0018]
According to an eighth aspect of the present invention, in any one of the first to fourth aspects, the third storage means for storing a host name and an address for accessing the own apparatus from the second network side; When the address stored in the storage means is accessed from the second network, it is sent to the server device from its own device response means for returning a predetermined response and from the device connected to the second network. Monitoring means for monitoring an address query for a host name. When the monitoring means receives an address query for a host name stored in the third storage means, the query is sent to the server device. A relay device that returns the response data including the address stored in the third storage means without relaying, to a device connected to the second network Even if the range of addresses to be assigned to specific is changed, by transmitting a communication packet from a device connected to a second network at a predetermined host name, it is possible to obtain the address of the relay device. In particular, when the relay device is set from a device connected to the second network, if the address of the relay device is dynamically changed, the setting itself may become difficult. Problems can be avoided.
[0019]
A ninth invention of the present invention is the relay device according to any one of the fifth to eighth inventions, wherein the inquiry is a DNS query, and an address range dynamically allocated to a device connected to the second network is Even when the change is made, if the device connected to the second network can transmit the DNS query, the address of the relay device can be obtained.
[0020]
According to a tenth aspect of the present invention, in the fifth or sixth aspect, a request from a device connected to the second network is made after the address range stored in the storage unit is changed by the address changing unit. If there is, it is a relay device having its own device address changing means for changing the address stored in the second storage means to one of the address ranges stored in the storage means, and stored in the second storage means Even in the case where the same address as that of the local device is present in the first network, it is possible to avoid the presence of the same address due to a request from a device connected to the second network. . Therefore, it is possible to avoid the access from the second network side to the first network side being hindered by the relay device.
[0021]
An eleventh invention of the present invention is the relay device provided with a physical switch for operating the own device address changing means in the tenth invention, and is a physical switch, so that the change is easy.
[0022]
A twelfth aspect of the present invention is the relay apparatus according to any one of the first to eleventh aspects, wherein the address is an IP address, and the problem of address duplication in an IP network can be avoided.
[0023]
A thirteenth aspect of the present invention is a relay apparatus that relays data packets between a first network and a second network, and an address range that is dynamically allocated to a device connected to the second network Storage means for storing in advance, detection means for detecting the address range of the first network, and determining whether the address range detected by the detection means and the address range stored in the storage means match or overlap Address duplication determination means, second storage means for storing an address for accessing the own device in the address range of the second network stored in advance in the storage means, and the second storage When a device connected to the second network accesses the address stored in the means, a predetermined response is returned. A relay that transmits a response indicating that there is an address range overlap to the device when the address overlap determination unit determines that there is an address range overlap. When the address assigned to the terminal under control overlaps with the address range of the first network, the information can be notified, so that the administrator of the second network can easily do the duplication. I can grasp it.
[0024]
In a fourteenth aspect of the present invention, in the thirteenth aspect, when there is a request from the device to cancel duplication of address ranges, the address range stored in the storage unit is detected by the detection unit. It is a relay apparatus having an address changing means for changing so as not to overlap with the range, and it is possible to avoid duplication with the address range of the first network by a request from a subordinate terminal.
[0025]
A fifteenth aspect of the present invention is the relay apparatus provided with a physical switch for operating the own apparatus address changing means in the fourteenth aspect, and is a physical switch, so that the change is easy.
[0026]
(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.
[0027]
FIG. 1 is a diagram showing a configuration of a network system including a relay device according to Embodiment 1 of the present invention.
[0028]
In FIG. 1, 1 is a wide area network such as the Internet, and 2 is a computer device (hereinafter referred to as a PC) connected to the wide area network 1. The computer device 2 has general-purpose browser means, and can access a web server 5 described later and display a web page.
[0029]
Reference numeral 3 denotes a DNS (Domain Name System) server, which stores an IP address assigned to a device connected to the wide area network 1 in association with a host name corresponding to the IP address assigned from the client via the wide area network 1. When the IP address of the device having the request is requested, the stored information is searched, and the IP address for the requested host name is transmitted to the client.
[0030]
4 is a DHCP server that dynamically assigns an IP address based on a request from a client terminal connected to the wide area network 1. Further, the DHCP server 4 has a client terminal removed from the wide area network 1. The IP address dynamically allocated in some cases is collected.
[0031]
A web server 5 provides a web page for access from the computer device 2 or the like. The web page is described in a markup language such as HTML, and may include a program such as Java (registered trademark).
[0032]
Reference numeral 6 denotes an upper relay apparatus connected to the wide area network 1 (which is a relay apparatus but is referred to as an upper relay apparatus in order to clarify the distinction from the relay apparatus 9 described below), and configures the first local network under the control. To do. Reference numeral 7 denotes a DHCP server connected to the first local network, and reference numeral 8 denotes a computer device (hereinafter referred to as a PC) connected to the first local network. This first local network is configured by the DHCP server 7, the PC 8, and the like. Communication between the PC 8 and the like connected to the first local network and the PC 2 and the like connected to the wide area network 1 becomes possible via the upper relay device 6.
[0033]
The DHCP server 7 is connected to the first local network and dynamically assigns an IP address to the upper relay apparatus 6 and the PC 8. The PC 8 also operates as a DHCP client. The range of IP addresses that can be assigned by the DHCP server 7 to devices in the first local network is set in advance, and IP addresses are assigned according to the setting contents. The assignment process is executed by making a request from a device connected to the first local network, and dynamically assigns an IP address to the device requested by the DHCP server 7.
[0034]
Next, 9 is a relay device (a router in the first embodiment of the present invention), 10 to 12 are computer devices (hereinafter referred to as PCs), and the relay device 9 is under the control of the PCs 10 to 12 and the web server 13. A second local network is configured. The PCs 10 to 12 and the web server 13 operate as DHCP clients. That is, when the PCs 10 to 12 and the web server 13 are connected to the second network, they request the later-described DHCP server unit 24 to assign an IP address, and the IP address assigned by the DHCP server unit 24 in response to the request. It is stored as the IP address of its own device.
[0035]
Next, the internal configuration of the relay apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 2 is an internal configuration diagram of the relay apparatus according to Embodiment 1 of the present invention. In FIG. 2, reference numeral 21 denotes a first network I / F unit for connecting to the first network, which is based on a protocol such as TCP / IP and is a first local network under the wide area network 1 and the upper relay device 6. Can be connected to.
[0036]
Reference numerals 22a to c denote local network I / F units, which can be connected to the PCs 10 to 12, the web server 13, etc., and connected to the local network I / F units 22a to 22c including the relay device 9 (via a hub or the like And a second local network as shown in FIG. 1.
[0037]
A web server unit 23 is configured to be accessible via the first network I / F unit 21 and the local network I / F units 22a to 22c. For example, when the IP address of the first network I / F 21 is assigned to “192.168.1.1” by the DHCP server 7, the PC 8 sends “Http://192.168.1.1:80”. Is transmitted to the relay device 9 by the higher-level relay device 6. Since this transmission packet is accessed by the port number 80, it is received by the web server unit 23 (port number 80). When accessed from the PC 8, the web server unit 23 responds to a predetermined web page according to the access contents, or requests the control means 26 described later to perform operations such as changing the setting contents of the relay device 9. To do.
[0038]
The DHCP server unit 24 receives an IP address assignment request from a device connected to the second network, and registers one of IP addresses not set in the DHCP assignment table 25b described later. An IP address is assigned to the device, and an OK response is returned.
[0039]
A storage unit 25 stores programs and various setting information. This storage means includes each storage means described below.
[0040]
Reference numeral 25a denotes a DHCP allocation address range storage unit, which stores in advance a range of IP addresses that can be dynamically allocated to devices under its control by the DHCP server unit 24. For example, when setting is made so that the range of “192.168.0.1” to “192.168.0.254” is allocated, the content “192.168.0.0/24” is set as the DHCP allocation address. It is stored in the range storage means.
[0041]
A DHCP allocation table storage unit 25b stores the IP address allocated to the subordinate terminal by the DHCP server unit 24 in the address range stored in the DHCP allocation address range storage unit 25a together with the MAC address of the terminal. is there. The DHCP allocation table storage unit 25b is configured as shown in FIG. 5, for example. FIG. 5 is a diagram showing the contents of the DHCP allocation table of the relay device according to Embodiment 1 of the present invention. In FIG. 5, the IP address “192.168.0.2” is assigned to the relay device 9, and the IP addresses “192.168.0.3” to “192.168.0.5” are assigned to the PCs 10 to 12, respectively. It is shown that.
[0042]
Reference numeral 25c denotes default address storage means. If the transmission packet from the second local network side is the IP address stored in the default address storage means 25c and the destination is the port number 80, the transmission is made. The packet data is notified to the web server unit 23. The contents of the default address storage means 25c are set in advance, and even if the storage contents of the DHCP allocation address range storage means 25a change, the storage contents of the default address storage means 25c will not change. Therefore, when the stored contents of the DHCP allocated address range storage unit 25a change, the address of the relay device 9 itself is changed, but the address of the web server unit 23 does not change. Note that the address of the web server unit 23 is effective only for access from the second local network side, and is not used for access from the first local network.
[0043]
Reference numeral 25 d denotes a web server unit host name storage unit that stores the host name of the web server unit 23. This content is set in advance, but may be changed by a predetermined operation.
[0044]
Reference numeral 25e denotes a local apparatus address storage unit that stores the IP address of the local apparatus, that is, the relay apparatus 9 itself. In the initial state, the smallest number in the address range stored in the DHCP assigned address range storage means 25a is assigned to the relay device 9 itself. For example, when “192.168.0.0/24” is set in the DHCP allocation address range storage unit 25a in the initial state, “192.168.0.1” is allocated to the own device address storage unit 25e. . When the address range stored in the DHCP assigned address range storage means 25a is changed, the smallest number is assigned to the relay device 9 itself.
[0045]
Reference numeral 26 denotes control means for controlling the entire relay apparatus 9, and includes various control means such as address duplication detection means 26a, address range setting means 26b, DNS inquiry monitoring means 26c. Reference numeral 27 denotes a push-type switch unit, which will be described in detail in the second embodiment.
[0046]
When the address detection means (not shown) detects the address range of the first local network, the address duplication detection means 26a determines the address range detected by the address detection means and the address range stored in the DHCP allocated address range storage means 25a. It is determined whether or not they match or overlap.
[0047]
When the address range setting unit 26b determines that there is an address range duplication in the address duplication detection unit 26a, the address range stored in the DHCP assigned address range storage unit 25a overlaps the address range detected by the address detection unit. Change to not.
[0048]
The DNS inquiry monitoring unit 26c monitors an address inquiry (for example, DNS query) for a host name transmitted from a device such as the PCs 10 to 12 connected to the second local network to the DNS server. When the query is detected, it is determined whether or not the host name included in the query matches the host name stored in the web server unit host name storage means 25d.
[0049]
The operation of the relay device 9 configured as described above will be described with reference to the flowchart of FIG. Reference is also made to FIGS. FIG. 3 is a flowchart for changing the address range of the relay device according to the first embodiment of the present invention.
[0050]
First, when the relay device 9 is turned on, the control unit 26 requests the DHCP server 7 preset in the storage unit 25 to assign an IP address on the first network I / F unit side (step 1). . Thereafter, it is determined whether or not there is an IP address assignment from the DHCP server 7 (step 2). If there is an IP address and subnet mask assignment, the IP address and subnet mask assigned in the storage means 25 are changed to the first address. 1 Registered as an IP address on the network I / F unit 21 side (step 3).
[0051]
An address detection unit (not shown) extracts the IP address and subnet mask on the first network I / F unit 21 side stored in the storage unit 25, extracts the address range of the first local network, and the address range Is notified to the address duplication detection means 26a (step 4). The address duplication detection unit 26a determines whether the address range stored in the DHCP assigned address range storage unit 25a overlaps or matches the IP address range detected and extracted by the address detection unit (step 5). For example, when the IP address “192.168.0.2” and the subnet mask “255.255.255.0” are assigned from the DHCP server 7, the range of “192.168.0.0/24” ( "192.168.0.0" to "192.168.0.255") are identified by the address detection means as being the IP address range of the network on the first network I / F unit 21 side. The range of “192.168.0.192/26” (“192.168.0.192” to “192.168.0.255”) is set in the DHCP allocated address range storage unit 25a. Then, it is determined by the address duplication detection means 26a that the address range overlaps in the portion of “192.168.0.192/26”. On the other hand, a range of “192.168.1.0/24” (“192.168.1.0” to “192.168.1.255”) is set in the DHCP allocated address range storage unit 25a. Then, since the address ranges do not overlap, the address duplication detection unit 26a determines that the address ranges do not overlap.
[0052]
If the address duplication detection unit 26a determines that there is duplication of address ranges, the address range stored in the DHCP assigned address range storage unit 25a is used as the first local network so that the address ranges do not overlap. (Step 6). For example, the IP address range of the network on the first network I / F unit 21 side is a range of “192.168.0.0/24”, and the DHCP assigned address range storage unit 25a stores “192.168.8.0. When the range of “192/26” is set, the range of the DHCP allocation address range storage unit 25a is changed to “192.168.1.192/24” and the IP address of the DHCP allocation table storage unit 25b To change. When there are two or more first network I / F units 21 and they are connected to different networks, the range of the DHCP allocated address range storage means 25a so as not to overlap with the address ranges of these two or more networks. Is changed by the address duplication detection means 26a.
[0053]
After step 6 or after determining that the address ranges do not overlap at step 5, the DHCP server unit 24 is turned on. After the DHCP server unit 24 is turned on, if there is an IP address assignment request from the PCs 10 to 12 which are DHCP clients, an unassigned IP address is searched from the DHCP assignment table storage means 25b, and the IPs searched for the PCs 10 to 12 are searched. The IP address assignment is returned to the PCs 10 to 12 while being registered in the DHCP assignment table storage unit 25b in association with the address (step 7).
[0054]
If no IP address is assigned at step 2, an IP address assignment request is made to the DHCP server at predetermined intervals.
[0055]
The IP address of the relay device 9 itself is automatically assigned to the DHCP assignment table storage unit 25b at the same time as the DHCP assignment table 25b is changed.
[0056]
In the first embodiment, the relay apparatus 9 is used as a DHCP client and the IP address on the first network I / F 21 side is dynamically acquired. However, it is determined whether or not the IP address is set by the user. Thereafter, operations from step 4 to step 7 may be performed.
[0057]
In addition, the network address range on the first network I / F unit 21 side is determined by the subnet mask and the IP address, but may be determined by CIDR (Classless Inter-Domain Routing).
[0058]
Further, the address duplication detection unit 26a may be performed at predetermined intervals after the relay device 9 is turned on, so that an interrupt is activated when the own device address storage unit 25e is rewritten. Also good.
[0059]
As described above, in the relay apparatus according to Embodiment 1 of the present invention, an address that does not overlap with the address range of the first local network can be assigned to a subordinate terminal. Further, since the address range of the first local network is determined based on the subnet mask and CIDR, the determination is easy.
[0060]
Next, the operation when accessing the web server unit 23 of the relay device 9 from the PCs 10 to 12 will be described with reference to FIGS. FIG. 4 is a flowchart for access of the relay device according to the first embodiment of the present invention.
[0061]
When the control unit 26 of the relay device 9 receives the transmission packet from the PC 10 via the local network I / F units 22a to 22c, the control unit 26 extracts the destination IP address included in the header portion of the transmission packet. It is determined whether it is an address (step 10). Whether or not the IP address of the relay device 9 is determined by the control means 26 based on whether or not it matches the IP address of the own device assigned to the DHCP assignment table storage means 25b. Then, when the destination IP address of the transmission packet is the IP address of the relay device 9, the control unit 26 further extracts the destination port number of the transmission packet and determines whether it is the port number (for example, 80) of the web server unit 23. It is determined whether or not (step 11). When the destination port number is the port number of the web server unit 23, the control unit 26 notifies the web server unit 23 of the contents of the transmission packet data. On the other hand, if the destination port number is not the port number of the web server unit 23, the contents corresponding to the port number are notified to the application corresponding to the port number and processed (step 12).
[0062]
If the control unit 26 determines in step 10 that the destination IP address is not the IP address of the relay device 9, it next determines whether or not the destination IP address is an IP address stored in the default address storage unit 25c. Determination is made (step 13). If it is determined that the IP address is stored in the default address storage unit 25c, the destination port number of the transmission packet is further extracted, and it is determined whether or not it is the port number (80 in this case) of the web server unit 23 (step 14). ). When the destination port number is the port number of the web server unit 23, the control unit 26 notifies the content of the transmission packet data to the web server unit 23 (step 15), and the web server unit 23 transmits the transmission packet data. In accordance with the request contents included in the data part, operations such as transmission of a web page and setting of the relay device 9 are performed (step 16).
[0063]
If the destination IP address is not the default IP address in step 13 or if the destination port number is not the port number of the web server unit 23 in step 14, the control means 26 determines whether or not the transmission packet is a DNS query. Judgment is made based on whether the number is well-known port “53” (step 17). When it is determined that the transmission packet is a DNS query, the control unit 26 determines whether or not the inquiry host name stored in the data portion of the transmission packet matches the web server unit host name (step 18). If they match, the IP address stored in the default address storage means 25c is transmitted as a DNS query response to the DNS query transmission source (step 19). The transmission packet to be transmitted as a response to the DNS query does not use the IP address of the own relay device 9 stored in the DHCP allocation table storage unit 25b as the transmission source, but the IP address stored in the default address storage unit 25c. As the sender.
[0064]
If they do not match, the control means 26 determines whether or not the IP address exists in the DHCP allocation table storage means 25b in order to determine whether it is addressed to its own network (step 20). The transmission packet is transferred from the first network I / F unit 21 to the first network side (step 21). On the other hand, when it is determined that the destination IP address exists in the DHCP allocation table storage unit 25b, the transmission packet is transferred to the corresponding local network I / F units 22a to 22c according to the DHCP allocation table storage unit 25b (step 22). ).
[0065]
The second network can also be configured to operate as a mere hub. In this case, the control unit 26 of the relay device 9 does not receive a packet, so there is no processing of step 20 and step 22. The process of step 21 is performed as it is. That is, if it is determined in step 17 that it is not a DNS query, or if it is determined in step 18 that it is not the host name of its own device, the received packet is transferred to the first network.
[0066]
In the above description, access to the default address that is not changed by the address range setting unit 26b is limited to the web server unit 23. However, the access is not limited to the web server unit, and access to other ports is also supported. You may make it process with an application.
[0067]
Further, it is possible to access the web server unit 23 of the relay device 9 with the host name without storing the default address in a fixed manner and storing only the host name, and vice versa. Access is possible, and either the IP address or the host name may be used instead of either one.
[0068]
Further, whether or not the DNS query includes a predetermined host name is not monitored for access to the DNS server 3, but the relay device 9 itself is provided with a DNS server function to access the DNS server unit. Alternatively, the above-described processing may be performed. In this case, instead of step 13, it is determined whether the destination IP address of the transmission packet matches the IP address for the entire relay device 9, and if it matches, it is determined whether it is a DNS query by the destination port number, and the transmission packet The inquiry host name included in the URL is determined according to whether or not it matches the web server part host name.
[0069]
As described above, even when the address range dynamically assigned to the device connected to the local network side is changed by the address range setting unit 26b, there is no change in the address for accessing the device in advance. The relay device can be accessed using the address, and the address of the relay device 9 can be obtained by transmitting a communication packet with a predetermined host name from a device connected to the second network (local network). Therefore, it can be avoided that the second network side address of the relay device 9 is unknown. In particular, when the relay device is set from a device connected to the second network, if the address of the relay device is dynamically changed, the setting itself may become difficult. Problems can be avoided.
[0070]
(Embodiment 2)
In the first embodiment, when the address duplication detection unit 26a determines that there is an address duplication, the address range setting unit 26b changes the address of the DHCP allocation address storage unit 25a. In the second embodiment, even if the address duplication detection unit 26a determines that there is an address duplication, the address range setting unit 26b is not operated until the relay device 9 receives a request from the PC 10 or the like. This will be specifically described below.
[0071]
The configuration of the relay apparatus according to the second embodiment of the present invention is basically the same as that shown in FIG. Reference numeral 27 denotes a push-type switch unit, which is configured so that the address range setting unit 26b operates when the switch unit is pushed.
[0072]
Hereinafter, the operation of the relay device 9 will be described in detail with reference to the flowchart of FIG. Refer to FIGS. FIG. 6 is a flowchart for changing the address range of the relay device according to the second embodiment of the present invention, and FIG. 7 is a diagram showing the contents of the web page of the relay device according to the second embodiment of the present invention. Steps 30 to 34 correspond to steps 1 to 5, respectively, and have the same operation, and thus description thereof is omitted.
[0073]
In step 34, when the address duplication detection unit 26a determines that there is an address range duplication and determines that there is an duplication, the control unit 26 generates a web page (display information) as shown in FIG. 7 that can be displayed on the computer device. (Step 35). Note that this web page can be stored in advance in the storage means 25 instead of being generated when an overlapping address range is detected.
[0074]
Next, in order to access the web server unit 23 from a terminal (PC 10-12, etc.) connected to the subordinate network, a transmission packet specifying the IP address of the relay device 9 and the port number of the web server unit 23 is sent. In the case (step 36), the web server unit 23 transmits the above-mentioned web page to the transmission source terminal of the transmission packet (step 37). This web page describes that the address ranges overlap between the first network and the second network as shown in FIG. 7 and the recommended change address range. Also, a button requesting the address range change on the second network (local network) side (“Yes” button in FIG. 7) and a button not requesting the address range change (“No” button in FIG. 7) are displayed. The information is described in a markup language such as HTML so that the information is transmitted to the web server unit 23 when the terminal side clicks and specifies this button with a mouse or the like.
[0075]
Here, when the “Yes” button is designated on the terminal side, the designation information is transmitted from the terminal to the web server unit 23 (step 38). When the web server unit 23 receives this designation information from the terminal, the address duplication detection unit 26a changes the address range of the DHCP allocated address range storage unit 25a so that the address ranges do not overlap (step 40). For example, the IP address range of the network on the first network I / F side is “192.168.0.0/24”, and the DHCP assigned address range storage unit 25a stores “192.168.0192 / 26 ”is set, the range of the DHCP allocation address range storage unit 25a is changed to the range of“ 192.168.1.192/24 ”and the IP address of the DHCP allocation table storage unit 25b To change. Further, the IP address stored in the own device address storage unit 25e is changed to a value within the range of “192.168.1.192/24” (for example, “192.168.1.193”).
[0076]
Although it has been described that the address range setting unit 26b is operated when the "Yes" button on the web page is designated on the terminal side, the address range setting unit 26b is operated by pressing the switch unit 27. You may make it make it. In addition, it is naturally possible to appropriately combine with the configuration of the relay apparatus of the first embodiment.
[0077]
As described above, according to the relay apparatus of the second embodiment, when the address assigned to the subordinate terminal overlaps with the address range of the first network, the information can be notified. The network administrator can easily grasp the duplication. In addition, duplication with the address range of the first network can be avoided by a request from a subordinate terminal.
[0078]
【The invention's effect】
According to the relay device of the present invention, communication packets can be smoothly relayed while avoiding duplication of addresses between networks.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a network system including a relay device according to Embodiment 1 of the present invention.
FIG. 2 is an internal configuration diagram of a relay apparatus according to Embodiment 1 of the present invention.
FIG. 3 is a flowchart for changing the address range of the relay device according to the first embodiment of the present invention;
FIG. 4 is a flowchart about access of a relay device in Embodiment 1 of the present invention;
FIG. 5 is a diagram showing the contents of a DHCP allocation table of a relay device in Embodiment 1 of the present invention.
FIG. 6 is a flowchart for changing an address range of a relay device in Embodiment 2 of the present invention;
FIG. 7 is a diagram showing the contents of a web page of a relay device in Embodiment 2 of the present invention.
[Explanation of symbols]
1 Wide area network
2,8,10,11,12 Computer device
3 DNS server
4,7 DHCP server
5 Web server
6 Host relay device
9 Relay device
21 First network I / F section
22a-c Local network I / F section
23 Web server
24 DHCP server part
25 Memory means
25a DHCP allocated address range storage means
25b DHCP allocation table storage means
25c default address storage means
25d Web server host name storage means
25e Self-device address storage means
26 Control means
26a Address duplication detection means
26b Address range setting means
26c DNS inquiry monitoring means
27 Switch part

Claims (15)

A relay device that relays data packets between a first network and a second network,
Storage means for storing a range of addresses dynamically allocated to devices connected to the second network;
Detecting means for detecting an address range of the first network;
Address duplication determination means for determining whether the address range detected by the detection means and the address range stored in the storage means match or overlap;
And an address changing unit that changes the address range stored in the storage unit so as not to overlap with the address range detected by the detecting unit when the address overlapping determining unit determines that there is an overlapping address range. A relay device characterized by that. 2. The relay apparatus according to claim 1, wherein the detection unit detects an address range of the first network based on an address of the own apparatus allocated from an address allocation apparatus of the first network. . A setting unit configured to set an address of the own device based on an input from the input unit; and the detection unit is configured to set an address range of the first network based on the address of the first network set by the setting unit. The relay device according to claim 1, wherein the relay device is detected. The relay device according to claim 2 or 3, wherein the detection unit detects an address range of the first network from a subnet mask or CIDR. A second storage means for fixedly storing an address at which the device can be accessed even when the address of the device is changed by the address changing device;
When there is an access from the second network to the address stored in the second storage unit, the device response unit returns a predetermined response.
After the address changing unit has changed the address range stored in the storage unit, and there is a transmission packet for the address stored in the second storage unit from the second network side, The relay apparatus according to any one of claims 1 to 4, wherein the own apparatus response means is operated without transferring to the first network side. After the address range stored in the storage unit is changed by the address changing unit, a transmission packet addressed to the address stored in the second storage unit from the second network side is sent to the network side. 6. The relay apparatus according to claim 5, wherein when operating the own apparatus response means without transmitting to the transmission apparatus, a transmission source address of a response packet is transmitted as an address stored in the second storage means. . Third storage means for storing a host name for accessing the device from the second network side and an address corresponding to the host name;
If the second network accesses the address stored in advance in the third storage means, the own device response means for returning a predetermined response;
A transfer means for transferring an address query for a host name from a device connected to the second network to a predetermined device;
When receiving an address query for the host name stored in the third storage means from a device connected to the second network, the address stored in the third storage means is used instead of operating the transfer means. The relay apparatus according to any one of claims 1 to 4, wherein the reply data is returned in response data. Third storage means for storing a host name and an address for accessing the device from the second network side;
If the address stored in the third storage means is accessed from the second network, the own device response means for returning a predetermined response;
Monitoring means for monitoring an address query for a host name, which is transmitted from a device connected to the second network to a server device;
When the monitoring means receives an inquiry about the address for the host name stored in the third storage means, the address stored in the third storage means is sent as response data without relaying the inquiry to the server device. The relay apparatus according to any one of claims 1 to 4, wherein the reply is included in the reply. The relay apparatus according to claim 5, wherein the inquiry is a DNS query. After the address range stored in the storage unit is changed by the address changing unit, when there is a request from a device connected to the second network, the address stored in the second storage unit is The relay apparatus according to claim 5 or 6, further comprising a local apparatus address changing means for changing to one of the address ranges stored in the storage means. The relay apparatus according to claim 10, further comprising a physical switch that operates the own apparatus address changing unit. The relay apparatus according to claim 1, wherein the address is an IP address. A relay device that relays data packets between a first network and a second network,
Storage means for storing in advance an address range to be dynamically allocated to devices connected to the second network;
Detecting means for detecting an address range of the first network;
Address duplication determination means for determining whether the address range detected by the detection means and the address range stored in the storage means match or overlap;
A second storage means for storing an address for accessing the own device in the address range of the second network stored in advance in the storage means;
When there is an access from a device connected to the second network with respect to the address stored in the second storage unit, the device response unit returns a predetermined response;
If the address duplication determination unit determines that there is an address range duplication, the own device response unit transmits a response indicating that the address range has duplication to the device. When there is a request to cancel the duplication of the address range from the device, it has an address changing unit that changes the address range stored in the storage unit so as not to overlap with the address range detected by the detecting unit. The relay apparatus according to claim 13. 15. The relay apparatus according to claim 14, further comprising a physical switch for operating the own apparatus address changing unit.

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