JP2013141060A - Relay server and relay communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relay server that is configured to rationally assign a virtual address in the case a virtual address is used to perform communication using a VPN.SOLUTION: A relay server 3 stores the addresses of object terminals 31, 32, 33 and the addresses of operation PCs 11, 12. The relay server 3 exchanges a routing object address with a relay server 1, and establishes a routing session. The relay server 3 assigns the received addresses of the operation PCs 11, 12 virtual addresses so that the network parts of the respective addresses of the operation PCs 11, 12 will be the same and will be different from the network part of a virtual address assigned to another relay server. The relay server 3 relays communication between routing object devices by use of the virtual addresses.

Description

  The present invention mainly relates to a relay server that enables communication between devices connected to different LANs (Local Area Networks).

  2. Description of the Related Art Conventionally, a communication technique called a virtual private network (VPN) that performs communication between LANs installed at physically separated locations is known. In the example shown in Patent Document 1, a relay server, a communication terminal, and the like are connected to each of a plurality of LANs installed at physically separated positions. A communication terminal can transmit a packet to a communication terminal connected to another LAN using this VPN. Specifically, a packet transmitted by a communication terminal is first sent to a relay server in the same LAN. This relay server transmits (transfers) the packet to the relay server in the same LAN as the destination communication terminal via the Internet. The relay server that receives this packet transmits (transfers) the packet to the destination communication terminal.

  By using this VPN, other remote LANs can be used as if they were directly connected networks.

JP 2010-268312 A

  By the way, in this type of system, terminals communicate with each other using private IP addresses of terminals connected to the LAN (hereinafter sometimes simply referred to as addresses). Therefore, when performing communication using VPN, it is necessary to transmit the address set in its own LAN to the LAN on the other side.

  In this regard, for example, when a VPN is constructed between the same companies, even if the other party knows the IP address, it is unlikely to be a problem. However, when a VPN is constructed between different companies, it is not preferable that the IP address is known to the other party from the viewpoint of security.

  In view of the above, the inventors of the present application have developed a configuration for performing communication by VPN using a virtual address. However, this configuration is a configuration in which virtual addresses registered in advance are sequentially assigned to the addresses of the communication terminals, and virtual addresses may be assigned sequentially to devices connected to different LANs.

  When virtual addresses are assigned in this way, it is conceivable that the user will be confused and a packet will be transmitted by specifying an incorrect address. Also, when specifying an address to restrict a remote desktop or the like, it is not possible to specify for each LAN, which is troublesome.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a relay server having a configuration in which virtual addresses are rationally allocated in the case of performing communication using VPN using virtual addresses. .

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to a first aspect of the present invention, a relay server having the following configuration is provided. That is, the relay server includes an address filter information storage unit, a virtual address allocation information storage unit, and a control unit. The address filter information storage unit is located in the first LAN (the relay server) is capable of transferring packets, and the first routing target address that is the address of the first routing target device and the second relay server located in the second LAN Stores the second routing target address that is the address of the second routing target device that can transfer the packet. The virtual address assignment information storage unit stores the second routing target address and the virtual address assigned to the second routing target address in association with each other. The control unit transmits the first routing target address to the second relay server, receives the second routing target address from the second relay server, and establishes a routing session with the second relay server. The controller, when assigning the virtual address composed of a network part and a host part to the received second routing target address, so that the network part is the same at each of the second routing target addresses, and The network unit is made different from the network unit of the routing target address other than the second routing target address, and the allocation relationship is stored in the virtual address allocation information storage unit. When the control unit receives a packet destined for the virtual address from the first routing target device, the control unit refers to the virtual address allocation information storage unit and associates the destination address of the packet with the virtual address. The packet is transferred to the routing session after being converted to the second routing target address. When the control unit receives a packet destined for the first routing target address from the routing session, the control unit refers to the virtual address allocation information storage unit to determine the source address of the packet as the second routing target address. And the packet is transferred to the destination first routing target device.

  Thereby, the segment of the virtual address of the routing object apparatus connected to the same LAN can be made the same. Therefore, it is possible to easily grasp the network configuration from the address while ensuring security. In addition, since the user can collectively specify the virtual addresses of the routing target devices connected to the same LAN, it is possible to restrict the remote desktop in units of LAN with a simple operation.

  The relay server preferably has the following configuration. That is, the control unit determines whether or not the virtual address has been assigned to another second routing target address when the virtual address is assigned to the second routing target address. If the virtual address has already been assigned to the other second routing target address, a new virtual address is assigned to the second routing target address so as to be the same as the network part of the assigned virtual address. .

  As a result, the network part of the virtual address assigned to the second routing target address can be reliably made the same.

  The relay server preferably has the following configuration. That is, the control unit determines whether or not the virtual address has been assigned to another second routing target address when the virtual address is assigned to the second routing target address. If the virtual address has not been assigned to the other second routing target address, a new virtual address is assigned to the second routing target so that the routing target address other than the second routing target address is different from the network unit. Assign to an address.

  As a result, even if a virtual address has not yet been assigned to the second routing target device, a new virtual address can be assigned so as not to cover other virtual addresses and the network unit.

  In the relay server, it is preferable that the network unit of the virtual address assigned to the second routing target address can be received in advance.

  Thereby, since the network part of the virtual address assigned to the second routing target address does not change every connection, the LAN indicated by the network part can be made easier to understand. Accordingly, it is possible to further reduce selection mistakes regarding the packet transmission destination or the remote desktop restriction target.

  In the relay server, it is preferable that the control unit automatically determines a network unit of the virtual address to be allocated to the second routing target address.

  Thereby, since it is not necessary to set in advance which virtual address is assigned to the routing target device, it is possible to save the user's trouble. In the above configuration, since one virtual address can be reused by a plurality of relay servers, the number of addresses reserved in advance as virtual addresses can be reduced. Accordingly, it is possible to flexibly cope with future network expansion and the like.

  In the relay server, the control unit preferably performs communication using the second routing target address when receiving an instruction to perform communication without using the virtual address.

  Thereby, even if there is no assignable virtual address, for example, the routing target devices can communicate with each other without redoing the VPN start process.

  According to a second aspect of the present invention, a relay server having the following configuration is provided. That is, the relay server includes an address filter information storage unit, a virtual address allocation information storage unit, and a control unit. The address filter information storage unit is located in the first LAN (the relay server) is capable of transferring packets, and the first routing target address that is the address of the first routing target device and the second relay server located in the second LAN Stores the second routing target address that is the address of the second routing target device that can transfer the packet. The virtual address assignment information storage unit stores the first routing target address and the virtual address assigned to the first routing target address in association with each other. The control unit allocates a plurality of sets of virtual addresses having different network units among the virtual addresses composed of a network unit and a host unit to a set of first routing target addresses, and assigns the allocation relationship to the virtual address Store in the allocation information storage unit. The control unit transmits the virtual address having a network part different from the virtual address transmitted to the relay server other than the second relay server to the second relay server, and transmits the second routing from the second relay server to the second routing server. A target address is received and a routing session is established with the second relay server. When the control unit receives a packet destined for the virtual address from the routing session, the control unit refers to the virtual address assignment information storage unit and sets the destination address of the packet corresponding to the virtual address to the first address. The packet is transferred to the routing target address and transferred to the destination first routing target device. When the control unit receives a packet destined for the second routing target device from the first routing target device, the control unit refers to the virtual address allocation information storage unit to determine the source address of the packet in the first routing target device. 2 Convert the packet to the virtual address transmitted to the relay server and transfer the packet to the routing session.

  As a result, since the network part of the virtual address transmitted by the relay server is different for each communication destination LAN, the access from the corresponding LAN can be restricted in a lump by invalidating the virtual address of the predetermined network part. Can do.

  According to the 3rd viewpoint of this invention, the relay communication system of the following structures is provided. That is, the relay communication system includes a first relay server and a second relay server. The first relay server located in the first LAN includes an address filter information storage unit, a virtual address allocation information storage unit, and a control unit. The address filter information storage unit includes a first routing target address that is an address of a first routing target device to which the first relay server can transfer a packet, and the second relay server located in a second LAN transfers the packet. And a second routing target address that is an address of a possible second routing target device. The virtual address assignment information storage unit stores a second routing target address and a virtual address assigned to the second routing target address in association with each other. The control unit transmits the first routing target address to the second relay server, receives the second routing target address from the second relay server, and establishes a routing session with the second relay server. The controller, when assigning the virtual address composed of a network part and a host part to the received second routing target address, so that the network part is the same at each of the second routing target addresses, and The network unit is made different from the network unit of the routing target address other than the second routing target address, and the allocation relationship is stored in the virtual address allocation information storage unit. When the control unit receives a packet destined for the virtual address from the first routing target device, the control unit refers to the virtual address allocation information storage unit and associates the destination address of the packet with the virtual address. The packet is transferred to the routing session after being converted to the second routing target address. When the control unit receives a packet destined for the first routing target address from the routing session, the control unit refers to the virtual address allocation information storage unit to determine the source address of the packet as the second routing target address. And the packet is transferred to the destination first routing target device.

  Thereby, the user can immediately grasp the communication status, the communication permission status, and the like. In addition, since the routing target devices connected to the same LAN can be specified collectively, for example, the use of the remote desktop can be easily restricted in units of LAN.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the whole structure of the relay communication system which concerns on one Embodiment of this invention. The functional block diagram of a relay server. The figure which shows the content of relay group information. The figure which shows the content of relay server information. The figure which shows the content of client terminal information. The figure which shows the content of VPN group information. The figure which shows the content of the address filter information registered beforehand in each relay server. The figure which shows the address filter information and virtual address which the relay server 3 memorize | stores after construction | assembly of VPN. The figure which shows the content of virtual address registration information, and the structure of a virtual address. The flowchart which shows the setting performed to a relay server beforehand. The flowchart which shows the process which produces a VPN group. The flowchart which shows the process which builds VPN. The flowchart which shows the process which builds VPN. The flowchart which shows the process which a relay server performs when allocating a virtual address. The flowchart which shows the routing control which a relay server performs when a packet is received from LAN. The flowchart which shows the routing control which a relay server performs when a packet is received from a routing session. Explanatory drawing which shows the routing control using a virtual address. The figure which shows the address filter information and virtual address which concern on another embodiment. Explanatory drawing which shows the routing control which concerns on another embodiment.

  Next, embodiments of the present invention will be described with reference to the drawings. First, an overview of the relay communication system 100 of the present embodiment will be described with reference to FIG. FIG. 1 is an explanatory diagram showing the overall configuration of the relay communication system 100 according to the present embodiment.

  As shown in FIG. 1, this relay communication system 100 includes a plurality of LANs 10, 20, and 30 connected to a wide area network (WAN) 80. Each of the LANs 10, 20, and 30 is a relatively small network constructed in a limited place. Further, the LANs 10, 20, and 30 are arranged at locations that are physically separated from each other. In the present embodiment, the Internet is used as the WAN 80.

  Each LAN will be specifically described below. As shown in FIG. 1, a relay server (second relay server) 1, operation PCs 11 and 12 as second routing target devices, and a client terminal 13 are connected to a LAN (second LAN) 10. . A relay server 2, an operation PC 21, and a client terminal 22 are connected to the LAN 20. Connected to the LAN (first LAN) 30 are a relay server (first relay server) 3, target terminals 31, 32 and 33 as first routing target devices, and a client terminal 34.

  Since each of the relay servers 1, 2, and 3 is connected not only to the LANs 10, 20, and 30 but also to the WAN 80, it can communicate with devices connected to the same LAN and is also arranged in another LAN. It is also possible to communicate with the relay server. The operation PCs 11, 12, and 21 are personal computers that are operated by an operator, for example. The target terminals 31, 32, and 33 are personal computers or file servers. For example, the operator operates the operation PC 11 or the like to request predetermined data from the target terminal 31 or the like, and the target terminal 31 It is assumed that the stored content of is updated. The client terminals 13, 22, and 34 are configured by, for example, a personal computer, and can communicate with each other via the relay servers 1, 2, and 3 to which the client terminals 13, 22, and 34 belong.

  Next, a detailed configuration of the relay servers 1, 2, and 3 will be described with reference to FIG. FIG. 2 is a functional block diagram of the relay server 3. Since the relay server 3 has substantially the same configuration as the relay servers 1 and 2, the relay server 3 will be mainly described below.

  As illustrated in FIG. 2, the relay server 3 includes a storage unit 50, a control unit 60, and an interface unit 70.

  The interface unit 70 performs communication with terminals in the LAN 10. The interface unit 70 performs communication with the WAN 80. The interface unit 70 performs an appropriate process on the packet received from the LAN 30 or the WAN 80 and outputs the packet to the control unit 60.

  The control unit 60 is a CPU having control and calculation functions, for example, and can execute various processes by a program read from the storage unit 50. The control unit 60 can control various communications according to protocols such as TCP / IP, UDP, and SIP. Specifically, the control unit 60 determines a destination of the received packet based on information indicated by the packet and information stored in the storage unit 50, and transmits the packet to the determined destination. Moreover, the control part 60 can update the memory content of the memory | storage part 50 based on the information received from the other terminal.

  The storage unit 50 is composed of, for example, a hard disk or a nonvolatile RAM, and can store various data. The storage unit 50 includes a relay group information storage unit 51, a relay server information storage unit 52, a client terminal information storage unit 53, a VPN group information storage unit 54, an address filter information storage unit 55, and a virtual address registration information storage. Unit 56 and virtual address allocation information storage unit 57. Hereinafter, the contents stored in the storage unit 50 will be described with reference to FIGS. 3 to 9. 3 to 9 are diagrams mainly showing the storage contents of the storage unit 50 of the relay server 3.

  The relay group information storage unit 51 stores relay group information indicating a relay group and a relay server that constitutes the relay group.

  As shown in FIG. 3, in the relay group information, a group tag and a site tag of a child element whose parent element is the group tag are described. In the group tag, group information 511 related to the relay group is described. As the group information 511, relay group identification information (“id”), last update time (“lastmod”), and relay group name (“name”) are described. In the site tag, group configuration information 512 related to the relay server that configures the relay group is described. In this group configuration information 512, identification information (“id”) of the relay server is described. Further, additional relay groups can be created. In this case, unique identification information different from other relay groups is given to the new relay group. As a result, settings such as data exchange only within a specific relay group are possible.

  This relay group information is shared between the relay servers 1, 2, and 3 that constitute the relay group. When a process for changing a relay group is performed in a certain relay server, the fact is transmitted to the other relay server and the relay group information is updated. In this way, relay group information is dynamically shared.

  The relay server information storage unit 52 stores relay server information indicating an outline of a relay server that performs relay communication and a client terminal that belongs to the relay server.

  In the relay server information shown in FIG. 4, a site tag described for each relay server and a node tag of a child element whose parent element is the site tag are described. In the site tag, server information 521 regarding the relay server 1 is described. As the server information 521, relay server identification information (“id”), a relay server name (“name”), and activation information (“stat”) are described. When the content of “stat” is “active”, it indicates that the relay server is logged in to the relay communication system 100, and when stat is blank, it indicates that the log-off is being performed. In a node tag that is a child element of the site tag, affiliation information 522 indicating a client terminal belonging to the relay server is described. The belonging information 522 includes the name of the relay group to which it belongs (“group”), the identification information of the client terminal (“id”), the name of the client terminal (“name”), and the identification information of the relay server to which it belongs. ("Site"). When the client terminal is not logged in to the relay communication system 100, “site” is blank.

  Note that the communication by the relay group is performed as follows based on the relay group information and the relay server information. For example, when a packet is transmitted from the client terminal 13 to the client terminal 22, the client terminal 13 first transmits the packet to the relay server 1 that is a relay server to which the client terminal 13 is connected. The relay server capable of exchanging packets can be grasped based on the above relay group information, and the identification information of the client terminal belonging to the relay server and the connection possibility can be determined based on the above relay server information. I can grasp it. Based on these pieces of information, the relay server 1 transfers the packet to the relay server 2 that is a relay server to which the client terminal 22 is connected. The relay server 2 that has received this packet transfers the packet to the client terminal 22. Thus, relay communication can be performed between the client terminals 13 and 22.

  As with the relay group information, the relay server information is shared between the relay servers 1, 2, and 3 that constitute the relay group. When a process for changing the relay server information is performed in a certain relay server, the fact is transmitted to the other relay server and the relay server information is updated. In this way, the relay server information is dynamically shared.

  The client terminal information storage unit 53 stores client terminal information that is detailed information about the client terminal. Note that the relay servers 1, 2, and 3 store only client terminal information related to client terminals belonging to the relay server. Since the client terminal 34 belongs to the relay server 3, only the client terminal information about the client terminal 34 is stored in the client terminal information storage unit 53 provided in the relay server 3.

  The client terminal information stored in the client terminal information storage unit 53 of the relay server 3 is shown in FIG. Similarly, the client terminal information stored in the relay server 1 is shown in FIG. 5A, and the client terminal information stored in the relay server 2 is shown in FIG. 5B.

  In the client terminal information shown in FIG. 5, a node tag is described. The node tag includes a private IP address (“addr”) of the client terminal, a name of the relay group to which the client terminal belongs (“group”), identification information (“id”), a name (“name”), a relay A password for logging in to the server (“pass”) and port information (“port”) are described.

  The VPN group information storage unit 54 stores VPN group information, which is information related to a VPN group configured by a relay server and a device selected as a routing point from the client terminal (hereinafter referred to as a routing device). ing. By establishing a routing session between routing devices belonging to the same VPN group, communication using VPN can be started.

  In the VPN group information shown in FIG. 6, a vnet tag is described. In this vnet tag, VPN group basic information 541, routing point information 542, and routing session information 543 are described. The VPN group basic information 541 includes a relay group name (“group”) to which the VPN group belongs, a VPN group identification information (“id”), a last update time (“lastmod”), and a VPN group name. ("Name"). The routing point information 542 describes identification information of a routing device that performs routing when communication is performed between VPN groups. In the example of FIG. 6A, a relay server 1 and a relay server 3 are described as routing devices. The routing session information 543 describes routing devices connected to each other in the VPN group. In the routing session information 543, the routing device first performs communication control (“sp (start point)”) in the routing session establishment process for establishing the VPN in the VPN group and starting communication, and its communication. It is determined separately for the control side (“ep (end point)”). In the following description, a routing device that first performs communication control for establishing a routing session may be referred to as a “start point”, and a routing device that receives the communication control may be referred to as a “end point”.

  From the VPN group information shown in FIG. 6A, it can be seen that the VPN group (VPN-GROUP 1) is composed of the relay server 1 and the relay server 3. It can also be seen that at the start of communication in the VPN-GROUP 1, communication control for establishing a routing session from the relay server 3 to the relay server 1 is performed. Similarly, from the VPN group information shown in FIG. 6B, it can be seen that VPN-GROUP 2 is composed of the relay server 2 and the relay server 3. Further, it can be seen that at the start of communication in the VPN-GROUP 2, communication control for establishing a routing session from the relay server 3 to the relay server 2 is performed.

  This VPN group information is also shared among relay servers belonging to the same VPN group, similarly to the relay server information and the relay group information. When a process for changing VPN group information is performed in a certain relay server, the fact is transmitted to other relay servers belonging to the same VPN group, and the VPN group information is updated. In this way, VPN group information is dynamically shared. The process for creating this VPN group will be described later.

  The address filter information storage unit 55 stores address filter information that is information used when performing routing control using VPN. The address filter information storage unit 55 stores information (address filter information of the relay server 3) indicating a device (routing target device) to which the relay server 3 itself can directly transmit a packet before the VPN is constructed. The address filter information includes the address of the routing target device (routing target address) and the name of the routing target device.

  FIG. 7C shows an example of address filter information registered in advance in the relay server 3 itself. In this example, it is described that devices to which the relay server 3 can directly transmit packets are the target terminals 31, 32, and 33. 7A shows the address filter information registered in advance in the relay server 1, and FIG. 7B shows the address filter information registered in advance in the relay server 2.

  As described above, the address filter information storage unit 55 of the relay server 3 stores only the address filter information shown in FIG. 7C before constructing the VPN. When the relay server 3 establishes a routing session with the relay server 1, for example, the relay server 3 transmits address filter information (FIG. 7C) registered in advance to the relay server 1 and addresses from the relay server 1. The filter information (FIG. 7A) is received. Then, the relay server 3 stores the address filter information of the relay server 1 in the address filter information storage unit 55 in association with the identification information of the relay server 1.

  As a result, the address filter information storage unit 55 of the relay server 3 stores the address filter information of the relay server 1 as shown in FIG. 8A in addition to its own address filter information. Similarly, the address filter information storage unit 55 of the relay server 1 stores the address filter information of the relay server 1 and the relay server 3. Then, the relay servers 1 and 3 perform routing control based on the acquired address (detailed control will be described later). Hereinafter, a routing target address (addresses of target terminals 31, 32, and 33) included in the address filter information of the relay server 3 is referred to as a first routing target address, and the routing target included in the address filter information of the relay server 1 The address (the address of the operation PCs 11 and 12) may be referred to as a second routing target address.

  In the present embodiment, when communication is performed by establishing a routing session between the relay server 1 and the relay server 3 (when communication is performed using VPN-GROUP 1), between the relay server 3 and the target terminals 31, 32, and 33. In communication, communication is performed using a virtual address without using the actual addresses of the operation PCs 11 and 12. As the virtual address, an address that does not overlap in the LAN 30 (an address that is not assigned to a device in the LAN 30 and that is not reserved) is registered in advance and stored in the virtual address registration information storage unit 56 of the relay server 3. Has been. In the present embodiment, the addresses shown in FIG. 9A are registered as virtual addresses.

  Similarly, when communication is established by establishing a routing session between the relay server 2 and the relay server 3 (when communication is performed using VPN-GROUP 2), communication between the relay server 3 and the target terminals 31, 32, and 33 is performed. The communication is performed using the virtual address without using the actual address of the operation PC 21.

  The relay server 3 exchanges the address filter information as described above, acquires the addresses of the operation PCs 11 and 12 (or the operation PC 21) from the relay server 1 (or the relay server 2), and assigns a virtual address to the address. The virtual address assignment information storage unit 57 stores a correspondence relationship (assignment relationship) between the received address and the virtual address.

  Note that the virtual address of this embodiment is described in the IPv4 format. In the following description, among the 32 bits, the first 24 bits are referred to as a network part, and the subsequent 8 bits are referred to as a host part (see FIG. 9B). In the present embodiment, the relay server 3 assigns virtual addresses so that the network unit is different for each connection destination LAN (that is, for each connection destination relay server).

  Specifically, virtual addresses (150.100.10.1) and (150.100.10.2) are assigned to the operation PCs 11 and 12, as shown in FIG. Further, a virtual address (180.50.10.1) is assigned to the operation PC 21 as shown in FIG.

  In this way, by assigning virtual addresses so that the network part is different for each LAN of connection destinations (for each relay server), just looking at the virtual address, the virtual addresses of the same LAN can grasp the connection destination of the relay server. can do. Therefore, it is possible to prevent the user from specifying an incorrect virtual address. In addition, since the user can specify the virtual addresses of the routing target devices connected to the same LAN as in (150.100.10.0/24), it is possible to easily specify in units of LANs. Remote desktop restrictions can be made.

  Next, preparation for performing communication using VPN will be described. First, the setting performed in advance in the relay server will be described with reference to FIG. 10, and the flow when creating a VPN group will be described with reference to FIG. FIG. 10 is a flowchart showing settings to be made to the relay server in advance. FIG. 11 is a flowchart showing processing for creating a VPN group. In the following, the relay server 3 is taken as an example, and the settings performed on the relay server 3 and the processing executed by the relay server 3 will be described. Processing can be executed.

  The setting to be made in advance in the relay server 3 includes registration of address filter information of the relay server 3 (S101). This registration is performed by a user using the relay communication system 100 by inputting an address (first routing target address) of a device or the like designated as a routing target device of the relay server 3 and a name by a predetermined method. . Here, it is assumed that the user has input the addresses and names of the target terminals 31, 32, and 33. The registered address filter information is stored in the address filter information storage unit 55.

  Next, when performing communication using a virtual address, the user registers an address that does not overlap within the LAN 30 to which the relay server 3 is connected as a virtual address (S102). The virtual address registered here is stored in the virtual address registration information storage unit 56.

  Hereinafter, the flow when creating a VPN group will be described. First, the user can display a VPN group setting screen by operating the client terminals 13, 22, 34, and the like. Here, a case where setting is performed using the client terminal 34 will be described. On the setting screen displayed on the client terminal 34, a plurality of relay groups to which the client terminal 34 belongs are displayed. The user selects a relay group for which a VPN group is to be constructed from the plurality of relay groups (S201).

  When a relay group is selected, a list of identification information of relay servers and client terminals that belong to the selected relay group and that can function as a routing point is displayed on the screen of the client terminal 34 (S202). Then, the user selects a relay server and a client terminal that function as a routing point in the VPN group to be constructed (S203). In this description, it is assumed that the relay server 1 and the relay server 3 are selected by the user.

  Then, based on the identification information of the selected relay server, the identification information of the routing point and the routing session information are created (S204). The VPN group information shown in FIG. 6A is created by adding VPN group identification information or the like to these pieces of information. The client terminal 34 transmits this VPN group information to the relay servers 1 and 3 belonging to the same VPN group (S205). Then, the relay servers 1 and 3 store the received VPN group information in the VPN group information storage unit 54. Thus, the VPN-GROUP 1 construction process configured by the relay servers 1 and 3 is completed. It is assumed that VPN-GROUP 2 composed of the relay servers 2 and 3 is also created at a predetermined timing.

  Next, a flow until communication using VPN in the constructed VPN group is started will be described with reference to FIGS. FIG. 12 and FIG. 13 are flowcharts showing processing performed until communication using VPN is started. FIG. 14 is a flowchart illustrating processing performed by the relay server 3 when assigning virtual addresses.

  The user can display the constructed VPN group on the screen by operating the client terminal 13 or the operation PC 11 or the like. Then, by selecting an appropriate VPN group from the displayed VPN groups (S301), a process for constructing the VPN can be performed. In this description, an example will be described in which the relay server 3 performs the start process of the VPN group created above (a VPN group composed of the relay servers 1 and 3).

  The relay server 3 first reads out address filter information associated with itself (S302). The information read here is the content registered in S101 (the content shown in FIG. 7C). Next, the relay server 3 reads the routing points belonging to the selected VPN group (S303). Thereby, the relay server 1 is read based on the contents of the VPN group information shown in FIG.

  Based on the relay server information, the relay server 3 first determines whether the relay server 1 is logged in (“stat” is active or blank) (S304). According to the relay server information shown in FIG. 4, since the relay server 1 is logged in, the relay server 3 transmits a VPN group start command together with the VPN group identification information to the relay server 1 (S305).

  When the relay server 3 receives a response from the relay server 1 in response to the start command (S306), the relay server 1 registers the relay server 1 as a routing point that is ready to construct a VPN (S307).

  Next, the relay server 3 determines whether there is another device belonging to the same VPN group (S308). Since the currently created VPN group is composed of only the relay server 1 and the relay server 3, there is no other device. If there is another device, the relay server 3 performs the processing of S304 to S307 this time for the device.

  Next, the relay server 3 extracts routing session information from the contents stored in the VPN group information storage unit 54 (S309 in FIG. 13). Then, the relay server 3 refers to the extracted routing session information, and determines whether or not a routing session starting from itself is described (S310). In the routing session information of FIG. 6A, it is described that itself (relay server 3) is the starting point in the routing session to be established between the relay server 1 and the relay server 3.

  Therefore, the relay server 3 establishes a routing session by performing predetermined communication control on the relay server 1 (S311). When performing this communication control, the address filter information is exchanged as described above (S312).

  Next, the relay server 3 assigns a virtual address to the routing target address included in the received address filter information (S313). This virtual address assignment is performed in detail according to the flowchart shown in FIG.

  Hereinafter, processing performed by the relay server 3 when assigning virtual addresses in the order of the operation PC 11 and the operation PC 12 will be described. The relay server 3 first determines whether a virtual address has been assigned to another device on the same LAN (S401). At present, since no virtual address is assigned to any of the operation PCs 11 and 12, the relay server 3 determines whether or not a virtual address having an unused network unit is registered in the virtual address registration information storage unit 56. Judgment is made (S402).

  When a virtual address having an unused network part is registered, a virtual address is assigned using the virtual address (S404). This makes it possible to newly assign a virtual address that is different from the virtual address assigned to another routing target device. Specifically, the relay server 3 assigns a virtual address (150.100.10.1) to the operation PC 11.

  Note that the network unit of the virtual address assigned to the operation PC 11 may use a configuration set in advance by the user, or the relay server 3 refers to the virtual address registration information storage unit 56 and uses an unused network unit. May be selected automatically.

  In the former case, since the network part of the virtual address assigned to the second routing target address does not change for each connection, the LAN indicated by the network part can be made easier to understand. On the other hand, in the latter case, since it is not necessary to set in advance which virtual address is assigned to the routing target device, it is possible to save the user's trouble. In the latter case, for example, the virtual address can be assigned to a relay server other than the relay server 1 after terminating the VPN with the relay server 1 and releasing the assignment of the virtual address. That is, since virtual addresses can be reused, it is possible to reduce the number of addresses reserved in advance as virtual addresses. Accordingly, it is possible to flexibly cope with future network expansion and the like.

  And the relay server 3 continues and performs the start process of the communication using VPN (S405). In addition, when the virtual address which has an unused network part is not registered, the relay server 3 notifies that to a user (S403).

  Next, the relay server 3 assigns a virtual address to the operation PC 12. This time, in the determination of S401, a virtual address has been assigned to another device (that is, the operation PC 11) of the same LAN. Therefore, the relay server 3 assigns a virtual address using the network part (150.100.10) of the already assigned virtual address (S406). As a result, a virtual address (150.100.10.2) is assigned to the operation PC 12. Next, the relay server 3 determines whether or not the virtual address has been successfully allocated (S407). If the relay server 3 succeeds in assigning the virtual address, the relay server 3 continues the communication start processing using the VPN (S405). On the other hand, if the allocation of the virtual address fails, the relay server 3 notifies the user to that effect (S408).

  When the relay server 3 notifies the error in S403 and S408, the relay server 3 inquires of the user whether or not to perform communication using the actual address (S409). The relay server 3 continues the communication start process using the VPN when the user is permitted to perform communication using the actual address (S405). Thereby, for example, communication can be appropriately started even when an emergency situation occurs or in a situation where the address may be known to the other party. On the other hand, when permission is not obtained from the user, the relay server 3 stops the start process.

  Next, the relay server 3 performs the process of S310 again. Even when it is determined that there is no duplication between the routing target addresses, the process of S310 is performed again. Since the currently created VPN group is composed of only the relay server 1 and the relay server 3, other routing sessions are not described in the VPN group information. Accordingly, the relay server 3 starts packet routing control (S316). If there is another routing session, the relay server 3 performs the processes of S311 to S314 again.

  As described above, in this embodiment, when a VPN is constructed, each routing device exchanges (acquires) address filter information with other routing devices. Therefore, the VPN is constructed using the latest address filter information. Can do. Therefore, even if the address filter information is changed in some routing devices at the stage before the VPN start, the VPN can be constructed and communication can be started with the change reflected in all the routing devices. Inconsistency in routing can be prevented, and reliability can be improved.

  Although not described in the flowchart of FIG. 13, even if there is no routing session that is the starting point of the connection in S310 (when it is the end point of routing), the routing device from the starting point Under the communication control, routing session establishment processing and address filter information exchange are performed. At the same time, when communication using virtual addresses is performed, virtual addresses are assigned.

  Each routing device does not perform the initial communication control for establishing a routing session unless the routing session information indicates that it is the starting point. The routing session can be established with simple control.

  As described above, the relay server 3 constructs a VPN with the relay server 1. Further, when the relay server 3 receives a VPN-GROUP 2 start instruction from the user, the relay server 3 also constructs a VPN for the relay server 2 in the same manner. Then, the relay server 3 assigns a virtual address having a network part different from that of the operation PCs 11 and 12 to the operation PC 21 by performing the process of FIG.

  Next, a process for routing a packet using the established routing session will be described.

  First, control performed when the relay server 3 receives a packet from the LAN 30 will be described with reference to FIG. FIG. 15 is a flowchart showing the flow of this control.

  Note that when a packet is transmitted to another routing target device, the routing target device in the LAN 30 acquires the other routing target address to be the destination by inquiring the relay server 3. At this time, when a virtual address is assigned, the relay server 3 returns a virtual address instead of an actual address in response to the inquiry made by the routing target device in the LAN 30 to the relay server 3. Therefore, for example, when a packet is transmitted from the target terminal 31 to the operation PC 11, the target terminal 31 acquires from the relay server 3 the virtual address (150.100.10.1) assigned to the operation PC 11 as the destination address. It will be.

  The relay server 3 stands by until a packet is received from the LAN 30 (S501). When a packet is received from the LAN 30, first, it is determined whether or not the destination of the packet is itself (relay server 3) (S502).

  When the packet destination is itself, the relay server 3 receives the packet (S503). On the other hand, when the destination of the packet is other than itself, the relay server 3 compares the destination address of the received packet with the address filter information (see FIG. 9A), and the destination address is the address filter. It is determined whether or not the information is registered (S504). When the destination address is not registered in the address filter information, the relay server 3 discards the packet (S505). On the other hand, when the destination address is registered in the address filter information, the relay server 3 specifies a routing session corresponding to the address filter information (S506).

  Next, the relay server 3 refers to the virtual address assignment information storage unit 57 and determines whether or not the destination address is a virtual address (S507). When the destination address is a virtual address, the relay server 3 converts the destination address into an actual address (S508), and transmits (transfers) the packet to the routing session specified in S506 (S509).

  Next, control performed when the relay server 3 receives a packet from the routing session will be described with reference to FIG. FIG. 16 is a flowchart showing the flow of this control.

  The relay server 3 stands by until a packet is received from the routing session (S601). When the relay server 3 receives the packet, the relay server 3 compares the destination address of the packet with the address filter information (see FIG. 8A), and the destination address of the packet becomes its own address filter information. It is determined whether or not they are registered in association with each other (S602).

  When the destination address of the packet is registered in association with its own address filter information, the virtual address assignment information storage unit 57 is referred to determine whether or not a virtual address is assigned to the source address ( S603). When a virtual address is assigned to the transmission source address, the relay server 3 converts the transmission source address into a virtual address (S604), and transfers the packet to the device (target terminals 31, 32, 33) indicated by the destination address. (S605). If a virtual address is not assigned to the transmission source address, the relay server 3 transfers the packet to the device indicated by the destination without converting the address (S605).

  Further, when the destination address is not registered in association with its own address filter information, the relay server 3 determines whether or not the destination address is registered in association with the address filter information of another routing device. This is performed (S606). When the destination address is registered in association with the address filter information of another routing device, the relay server 3 identifies the corresponding routing session (S607), and transmits (transfers) the packet to this routing session ( S608).

  On the other hand, when the destination address is not registered in the address filter information of another routing device, the relay server 3 discards the packet (S609).

  By performing the above control, communication by the relay communication system 100 can be performed using the virtual address.

  Next, a flow when the operation PC 11 and the target terminal 31 exchange packets via the relay server 3 that performs the above control will be briefly described with reference to FIG.

  FIG. 17A shows a case where a packet is transmitted from the target terminal 31 to the operation PC 11. In this case, the relay server 3 performs the control shown in FIG. 15 in order to receive a packet from the LAN 30.

  The target terminal 31 transmits a packet with the virtual address of the operation PC 11 as the destination address as described above. The relay server 3 that has received this packet recognizes that the relay server 1 is described as a routing device corresponding to the destination address of the packet based on the address filter information (see FIG. 9A) and performs routing. A session is specified (S506). Next, the relay server 3 recognizes that the destination address is a virtual address, and converts the destination address into an actual address (S508). Then, the relay server 3 transmits a packet to the relay server 1 via the routing session (S509).

  The relay server 1 that has received this packet recognizes that itself (relay server 1) is described as a routing device corresponding to the destination address of the packet based on the address filter information. Then, the relay server 1 transmits the packet to the destination operation PC 11.

  FIG. 17B shows a case where a packet is transmitted from the operation PC 11 to the target terminal 31. In this case, the relay server 3 performs the control shown in FIG. 16 in order to receive a packet from the routing session.

  The operation PC 11 transmits a packet with the actual address of the target terminal 31 as the destination address. The relay server 1 that has received this packet recognizes that the relay server 3 is described as a routing device corresponding to the destination address of the packet. And the relay server 1 performs the process which transmits a packet to the relay server 3 via a routing session.

  The relay server 3 that has received this packet recognizes that itself (the relay server 3) is described as a routing device corresponding to the destination address of the packet based on the address filter information (see FIG. 8B). To do. Then, the relay server 3 refers to the virtual address assignment information storage unit 57 and recognizes that the virtual address is assigned to the transmission source address. Then, the relay server 3 converts the transmission source address into a virtual address (S604), and transmits the packet to the destination target terminal 31 (S605).

  As described above, packets can be exchanged between the operation PC 11 and the target terminal 31 while hiding the actual address of the operation PC 11. Therefore, communication can be performed between the routing target devices while ensuring security.

  As described above, the relay server 3 of this embodiment includes the address filter information storage unit 55, the virtual address allocation information storage unit 57, and the control unit 6060. The address filter information storage unit 55 stores the first routing target address (addresses of the target terminals 31, 32, and 33) and the second routing target address (addresses of the operation PCs 11 and 12). The virtual address assignment information storage unit stores the second routing target address and the virtual address assigned to the second routing target address in association with each other. The control unit 60 exchanges routing target addresses with the relay server 1 to establish a routing session. The control unit 60 assigns a virtual address so that the network unit is the same for the addresses of the operation PCs 11 and 12 and is different from the network unit of the virtual address assigned to the relay server 2. When receiving a packet whose destination is a virtual address from the first routing target device, the control unit 60 converts the destination address of the packet into a second routing target address and transfers the packet to the routing session. When receiving a packet destined for the first routing target address from the routing session, the control unit 60 converts the packet source address into a virtual address and transfers the packet to the destination target terminals 31, 32, and 33. .

  Thereby, the segment of the virtual address of the routing object apparatus connected to the same LAN can be made the same. Therefore, it is possible to easily grasp the network configuration from the address while ensuring security. In addition, since the user can collectively specify the virtual addresses of the routing target devices connected to the same LAN, it is possible to restrict the remote desktop in units of LAN with a simple operation.

  Next, an embodiment having a configuration different from the above embodiment will be described. FIG. 18 is a diagram illustrating address filter information and virtual addresses according to another embodiment. FIG. 19 is an explanatory diagram illustrating routing control according to another embodiment. In the following description, members that are the same as or similar to those in the above embodiment are denoted by the same reference numerals in the drawings, and description thereof may be omitted.

  In the above embodiment, the relay server 3 assigns virtual addresses to the routing target devices (that is, the operation PCs 11, 12, and 21) of other relay servers. On the other hand, in this embodiment (another embodiment), the relay server 3 assigns a virtual address to its own routing target device (that is, the target terminals 31, 32, 33).

  Accordingly, the relay server 3 assigns a virtual address before the exchange of the address filter information, not after the exchange, and transmits the assigned virtual address to another relay server. Further, the relay server 3 assigns virtual addresses so that the network unit is different for each relay server as the communication destination (that is, the network unit is different between the relay server 1 and the relay server 2). That is, in this embodiment, a plurality of sets of virtual addresses correspond to a set of routing target devices.

  As described above, the relay servers 1 and 2 store address filter information as shown in FIGS. 18A and 18B, respectively.

  Further, when communication is performed using this virtual address, communication can be performed appropriately by making the address conversion method different from that of the above embodiment. That is, when the relay server 3 receives a packet from the first routing target device (target terminals 31, 32, 33), the relay server 3 converts the source address, not the destination address, into a virtual address. On the other hand, when receiving the packet from the routing session, the relay server 3 converts the destination address instead of the transmission source address into an actual address.

  Thereby, since the network part of the virtual address transmitted by the relay server 3 is different between the relay server 1 and the relay server 2 as communication destinations, the virtual address including any one of the network parts is invalidated collectively (for example, ( By invalidating 150.100.20.0/24), access from the corresponding LANs can be restricted collectively.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  The partition between the network part and the host part in the virtual address is not limited to the position shown in the above embodiment. For example, the first 16 bits may be a network part and the remaining 16 bits may be a host part.

  An IPv6 format IP address may be used instead of the IPv4 format IP address. In this case, the virtual address may be IPv6 as well.

  The timing for assigning the virtual address is arbitrary. For example, the address filter information may be exchanged together with the transmission of the start command, and the virtual address may be assigned immediately thereafter.

  In the above, only the relay server functions as a routing point. However, the client terminal may function as a routing point. Further, the number of routing points in the VPN group is not limited to two and may be three or more. One routing device may belong to a plurality of VPN groups.

  The format for storing the relay group information, relay server information, client terminal information, VPN group information, address filter information, etc. is not limited to the XML format, and each information can be stored in an appropriate format.

  Instead of the above-described configuration, an external server used for communication between each relay server may be installed on the Internet, and a communication may be performed by exhibiting a function as a SIP (Session Initiation Protocol) server.

1 Relay server (second relay server)
3 Relay server (first relay server)
11, 12 Operation PC (second routing target device)
31, 32, 33 Target terminal (first routing target device)
10 LAN (second LAN)
30 LAN (first LAN)
54 VPN Group Information Storage Unit 55 Address Filter Information Storage Unit 56 Virtual Address Registration Information Storage Unit 57 Virtual Address Assignment Information Storage Unit 60 Control Unit 100 Relay Communication System

Claims (8)

A first routing target address that is an address of a first routing target device that is located in the first LAN and can transfer a packet, and an address of a second routing target device that can be transferred by a second relay server located in the second LAN An address filter information storage unit for storing the second routing target address,
A virtual address assignment information storage unit that stores the second routing target address and the virtual address assigned to the second routing target address in association with each other;
A control unit,
The controller is
A control for transmitting the first routing target address to the second relay server, receiving the second routing target address from the second relay server, and establishing a routing session with the second relay server;
When allocating the virtual address composed of a network unit and a host unit to the received second routing target address, the network unit is the same in each of the second routing target addresses, and the network unit is Control different from the network portion of the routing target address other than the second routing target address, and storing the allocation relationship in the virtual address allocation information storage unit;
When a packet destined for the virtual address is received from the first routing target device, the destination address of the packet is referred to the second routing target corresponding to the virtual address by referring to the virtual address allocation information storage unit Control to convert the address into a packet and transfer the packet to the routing session;
When a packet destined for the first routing target address is received from the routing session, the source address of the packet is allocated to the second routing target address with reference to the virtual address allocation information storage unit Control for converting the packet into a virtual address and transferring the packet to the destination first routing target device;
The relay server characterized by performing. The relay server according to claim 1,
The controller determines whether the virtual address has been assigned to another second routing target address when the virtual address is assigned to the second routing target address;
If the virtual address has already been assigned to the other second routing target address, a new virtual address is assigned to the second routing target address so as to be the same as the network part of the assigned virtual address. A relay server characterized by that. The relay server according to claim 1 or 2,
The controller determines whether the virtual address has been assigned to another second routing target address when the virtual address is assigned to the second routing target address;
If the virtual address has not been assigned to the other second routing target address, a new virtual address is assigned to the second routing target so that the routing target address other than the second routing target address is different from the network unit. A relay server that is assigned to an address. A relay server according to any one of claims 1 to 3,
The controller is
The relay server, wherein a network part of the virtual address assigned to the second routing target address can be received in advance. A relay server according to any one of claims 1 to 3,
The said control part determines automatically the network part of the said virtual address allocated to a said 2nd routing object address, The relay server characterized by the above-mentioned. A relay server according to any one of claims 1 to 5,
When the control unit receives an instruction to perform communication without using the virtual address, the control unit performs communication using the second routing target address. A first routing target address that is an address of a first routing target device that is located in the first LAN and can transfer a packet, and an address of a second routing target device that can be transferred by a second relay server located in the second LAN An address filter information storage unit for storing the second routing target address,
A virtual address assignment information storage unit that stores the first routing target address and the virtual address assigned to the first routing target address in association with each other;
A control unit,
The controller is
Among the virtual addresses composed of a network part and a host part, a plurality of sets of virtual addresses having different network parts are assigned to a set of first routing target addresses, and the assignment relation is stored in the virtual address assignment information storage part. Control to memorize,
The virtual address transmitted to the second relay server is different from the virtual address transmitted to the relay server other than the second relay server, and the second routing target address is received from the second relay server. Control for establishing a routing session with the second relay server;
When a packet destined for the virtual address is received from the routing session, the destination address of the packet is converted into the first routing target address corresponding to the virtual address with reference to the virtual address allocation information storage unit And a control for transferring the packet to the first routing target device as a destination,
When a packet destined for the second routing target device is received from the first routing target device, the source address of the packet is transmitted to the second relay server with reference to the virtual address allocation information storage unit Control to convert the virtual address to the packet and transfer the packet to the routing session;
The relay server characterized by performing. In the relay communication system including the first relay server and the second relay server,
The first relay server located in the first LAN is
A first routing target address which is an address of a first routing target device to which the first relay server can transfer a packet, and a second routing target device to which the second relay server located in the second LAN can transfer a packet. An address filter information storage unit that stores a second routing target address that is an address;
A virtual address assignment information storage unit that stores a second routing target address and a virtual address assigned to the second routing target address in association with each other;
A control unit,
The controller is
A control for transmitting the first routing target address to the second relay server, receiving the second routing target address from the second relay server, and establishing a routing session with the second relay server;
When allocating the virtual address composed of a network unit and a host unit to the received second routing target address, the network unit is the same in each of the second routing target addresses, and the network unit is Control different from the network portion of the routing target address other than the second routing target address, and storing the allocation relationship in the virtual address allocation information storage unit;
When a packet destined for the virtual address is received from the first routing target device, the destination address of the packet is referred to the second routing target corresponding to the virtual address by referring to the virtual address allocation information storage unit Control to convert the address into a packet and transfer the packet to the routing session;
When a packet destined for the first routing target address is received from the routing session, the source address of the packet is allocated to the second routing target address with reference to the virtual address allocation information storage unit Control for converting the packet into a virtual address and transferring the packet to the destination first routing target device;
A relay communication system.

Images