JP2012203760A - Connection destination restriction system and connection destination restriction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a terminal from logically and directly connecting to an external server and the like.SOLUTION: A communication management server 11 intermittently broadcasts a key packet to an internal network 4 by executing key packet transmission AP 21. A local terminal 15 (a remote terminal 16) receives information broadcasted to the internal network by executing key packet reception AP 23 and sets a reception flag based on whether or not the key packet from the communication management server 11 has been received. The local terminal (the remote terminal 16) determines whether or not it is physically connected to the internal network 4 based on the reception flag by executing connection destination restriction AP 25 and executes connection processing to a logical connection request if it is determined that it is physically connected to the internal network 4.

Description

  The present invention includes a terminal physically connected to an internal network and an external network, a communication management server physically connected to the internal network, and a connection destination restriction system that restricts a logical connection destination of the terminal. It is about.

  Conventionally, security of taking out PCs (personal computers), PDAs (personal digital assistants), mobile phones, tablet terminals, smartphones, etc. (hereinafter simply referred to as “terminals”) used outside the company. A problem in the field is pointed out. These terminals can be logically directly connected to the Internet, a home LAN (local area network), or the like without any restrictions. Here, “logically directly connected to the Internet or home LAN (local area network)” means, for example, an external server via the Internet if the communication is based on TCP / IP (Transmission Control Protocol / Internet Protocol). This means a connection form in which the IP address and port number (address information) of other terminals installed at home or the like are connected, and the terminal is physically connected directly to a communication device installed in an external network ( Including wired and wireless).

  If the terminal is logically directly connected to the Internet or home LAN, it may not be possible to restrict access to websites on the Internet or detect that the anti-will software pattern file has not been updated. Risk increases. In addition, when a terminal is logically directly connected to the Internet, a home LAN, or the like, a communication trail cannot be acquired, so that it is easy to intentionally leak information.

For example, Patent Document 1 discloses a network as described below for the purpose of preventing a computer in which an illegal program such as a virus or spyware has invaded from being connected to a secure network such as an in-house LAN. A connection control method is disclosed.
(1) When the user terminal 10 is activated and attempts to connect to the in-house LAN, the connection to the network is temporarily stopped, and the user terminal 10 is compared with the environment in which the user terminal 10 was operated last time or with the in-house LAN environment. Is called.
(2) If there is no change from the previous operating environment, the connection to the in-house LAN is restored as it is. However, if it is determined that the connection was made outside the in-house LAN during the previous operation, the anti-virus software is the latest version. After confirming this, the virus is examined.
(3) After the safety of the user terminal 10 is confirmed, the connection to the in-house LAN is restored.
(4) If it is determined that the internal LAN environment is not established, the connection is made to the external network as it is.

JP 2007-213550 A

  However, the mechanism described in Patent Document 1 cannot prevent a terminal from being logically directly connected to an external network in the first place. In addition, at least website access restrictions on the Internet and acquisition of communication trails are not possible. Therefore, it is impossible to improve the situation where the security risk for the terminal is high and the situation where it is easy to intentionally leak information.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a connection destination restriction system that can prevent a terminal from being logically directly connected to an external server or the like. It is to be.

In order to achieve the above-described object, the first invention includes a terminal physically connected to an internal network and an external network, and a communication management server physically connected to the internal network. The communication management server intermittently broadcasts permission information indicating that a logical connection request of the terminal is permitted to the internal network. Broadcast transmission means for transmitting, wherein the terminal receives the permission information by first broadcast reception means for receiving information broadcast to the internal network and the first broadcast reception means. Then, a first determination unit that determines that it is physically connected to the internal network, and the first determination unit that is physically connected to the internal network by the first determination unit. If it is determined that, based on the logical connection request, a connection destination limiting system, characterized in that it comprises a first connection means for executing connection processing, the.
According to the first invention, it is possible to prevent the terminal from being logically directly connected to an external server or the like.

The connection destination restriction system of the first invention further includes a VPN server physically connected to the internal network, and the VPN server receives information broadcast to the internal network. When the permission information is received by the broadcast receiving means and the second broadcast receiving means, a second determination means for determining that it is physically connected to the internal network, and a VPN connection from the terminal And a transmission unit that transmits a determination result of the second determination unit to the terminal when the request is received, and the terminal is not physically connected to the internal network by the first determination unit. If it is determined, the VPN connection request is transmitted to the VPN server, and the VPN server sends an object to the internal network from the VPN server. A third determination unit that determines that the connection to the valid VPN server is received when the determination result indicating that the connection is established is established, and that the third determination unit is connected to the valid VPN server When it is determined, it is preferable to include second connection means for executing VPN connection processing in response to the logical connection request.
As a result, even when the terminal is physically connected to an external network, a logical connection request is executed by VPN connection processing while preventing the terminal from being directly connected to an external server or the like logically. can do.

Further, the first connection means and the second connection means in the first invention always respond to the logical connection request, and the third determination means is the VPN server stored in advance in the terminal It is desirable to make the VPN connection only by using the address information.
As a result, it is possible to prevent a user who uses the terminal outside the company from accessing a server other than a valid VPN server by using a network adapter different from that instructed by the administrator.

A second invention includes a terminal physically connected to an internal network and an external network, and a communication management server physically connected to the internal network, and a connection for restricting a logical connection destination of the terminal A connection destination restriction method in a destination restriction system, wherein the communication management server intermittently broadcasts permission information indicating that a logical connection request of the terminal is permitted to the internal network. One step, a second step in which the terminal receives information broadcast to the internal network, and when the terminal receives the permission information in the second step, the terminal is physically connected to the internal network. A third step of determining that the terminal is connected to the network, and the terminal is physically connected to the internal network in the third step. If it is determined that, based on the logical connection request, and a fourth step of executing a connection process, a connection destination limiting method, which comprises.
According to the second invention, it is possible to prevent the terminal from being logically directly connected to an external server or the like.

  According to the present invention, it is possible to provide a connection limit system that can prevent a terminal from being directly and logically connected to an external server or the like. As a result, it is possible to improve the situation where the security risk for the terminal is high and the situation where it is easy to intentionally leak information.

The figure which shows the outline of the connection restriction system 1 Hardware configuration diagram of computer 30 The figure which shows the structure of connection destination restriction | limiting AP25. The flowchart which shows the process implement | achieved by key packet transmission AP21 The flowchart which shows the process implement | achieved by key packet reception AP23 The flowchart which shows the process implement | achieved by connection destination restriction | limiting AP25 and VPN connection AP24. The flowchart which shows the process implement | achieved by communication trail management AP22

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the configuration of the connection destination restriction system 1 will be described with reference to FIGS.
In the embodiment of the present invention, for example, OSI (Open Systems
The connection at the physical layer level in the Interconnection) reference model is referred to as “physical connection”. Further, for example, the connection from the data link layer to the application layer level in the OSI reference model is referred to as “logical connection”.
In the connection destination restriction system 1 according to the embodiment of the present invention, a “logical connection” partner (for example, IP address and port number in the case of communication by TCP / IP) is set to a secure network (for example, a company). It is intended to be limited to computers installed in the internal network.

  FIG. 1 is a diagram showing an outline of the connection destination restriction system 1. As shown in FIG. 1, in the embodiment of the present invention, an internal network 4, a communication management server 11, a business server 12, a firewall 13, a VPN (Virtual Private Network) server 14, a local terminal 15, etc. Is assumed to exist. In the embodiment of the present invention, it is assumed that the external network 5, the remote terminal 16, the external server 17, and the like exist outside the company 3.

  For convenience of explanation, different symbols are attached to the local terminal 15 and the remote terminal 16, but the difference between them is only the location, and the hardware and software are the same. That is, when the local terminal 15 is taken outside the company 3, it becomes the remote terminal 16.

The configuration of the connection destination restriction system 1 that is essential for preventing the local terminal 15 (remote terminal 16) from being logically directly connected to an external server or the like includes the communication management server 11 and the local terminal 15 (remote terminal 16). ).
The configuration of the connection destination restriction system 1 that is indispensable for the remote terminal 16 to execute a logical connection request by the VPN connection processing to the legitimate VPN server 14 includes the communication management server 11, the VPN server 14, and the remote Terminal 16.

Examples of the internal network 4 include an in-house LAN of a company or the like, an in-house WAN (wide area network) in which LANs installed at a plurality of bases are connected by a dedicated line or the like. In FIG. 1, a firewall 13 is illustrated as a physical network device constituting the internal network 4. Examples of other network devices include routers (both wired and wireless), switches, hubs, and relay servers.
The communication management server 11, business server 12, VPN server 14, and local terminal 15 are physically connected to the internal network 4. Here, the physical connection form may be wired or wireless.
VPN (Virtual Private Network) is a service that can use a public line as if it were a dedicated line, and security equivalent to that of the internal network 4 is ensured.

Here, the communication management server 11, business server 12, firewall 13, VPN (Virtual
A hardware configuration of a computer for realizing the private network server 14, the local terminal 15 (remote terminal 16), the external server 17, and the like will be described.

FIG. 2 is a hardware configuration diagram of the computer 30. Note that the hardware configuration in FIG. 2 is an example, and various configurations can be adopted depending on the application and purpose.
The computer 30 is connected to a control unit 31, a storage unit 32, an input unit 33, a display unit 34, a communication control unit 35, and the like via a bus 36.

  The control unit 31 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and the like. The CPU calls a program stored in the storage unit 32, a recording medium, etc. to a work memory area on the RAM, executes it, drives and controls each device connected via the bus 36, and realizes processing performed by the computer 30 To do. The RAM is a volatile memory, and temporarily stores a program, data, and the like loaded from the storage unit 32, the recording medium, and the like, and includes a work area used by the control unit 31 for performing various processes.

The storage unit 32 is a ROM (Read Only Memory), a flash memory, an HDD (hard disk drive), or the like, and stores a program executed by the control unit 31, data necessary for program execution, and the like. With respect to the program, a control program corresponding to a basic input / output system (BIOS), a boot loader, an operating system (OS), and an application program for causing the control unit 31 to execute processing to be described later are stored. Each of these program codes is read by the control unit 31 as necessary, transferred to the RAM, read by the CPU, and executed as various means.
The storage unit 32 may be an external storage device (USB memory, external hard disk, etc.) connected via a USB (Universal Serial Bus) or the like.

The input unit 33 inputs data and includes, for example, a keyboard, a pointing device such as a mouse, and an input device such as a numeric keypad. An operation instruction, an operation instruction, data input, and the like can be performed on the computer 30 via the input unit 33.
The display unit 34 includes a display device such as a CRT monitor and a liquid crystal panel, and a logic circuit (such as a video adapter) for realizing the video function of the computer 30 in cooperation with the display device.
The communication control unit 35 includes a communication control device, a communication port, and the like, and is a communication interface that mediates communication between the computer 30 and the internal network 4 or the external network 5. The communication control between the computers 30 is performed. As described above, the internal network 4 or the external network 5 may be wired or wireless.
The bus 36 is a path that mediates transmission / reception of control signals, data signals, and the like between the devices.

Returning to the description of FIG.
Each apparatus (terminal and server) shown in FIG. 1 may be one or plural. Each server may be realized by one casing (computer 30) or may be realized by a plurality of casings. For example, in the case of the communication management server 11, both the key packet transmission AP (application program) 21 and the communication trail management AP 22 may be installed in one casing, or may be installed in separate casings. good.

In the communication management server 11, a key packet transmission AP 21, a communication trail management AP 22, and the like are installed.
The key packet transmission AP 21 is an application program for causing the communication management server 11 to execute processing shown in FIG.
The control unit 31 of the communication management server 11 executes the key packet transmission AP 21 to allow permission information (hereinafter referred to as “key packet”) indicating that a terminal logical connection request is permitted to the internal network 4. .) Intermittently.

Specifically, the communication management server 11 intermittently transmits key packets by, for example, IP (Internet Protocol) level broadcast communication. In IP level broadcast communication, a key packet is transmitted by setting a transmission destination address to a special address called “broadcast address”.
The key packet is not particularly limited, but for example, it is desirable to have different contents depending on the time zone, such as a one-time password. Further, for example, the key packet may be encrypted and transmitted, and only the legitimate VPN server 14 and the local terminal 16 can be decrypted.

As the broadcast address, for example, a so-called limited broadcast address or a directed broadcast address can be designated.
The limited broadcast address is an IP address in which all bits are 1. For example, in the case of IPv4 (Internet Protocol version 4), “255.255.255.255” is the limited broadcast address. When broadcast communication is performed by specifying a limited broadcast address, a key packet is transmitted to all computers 30 in a network segment (a collision segment in the case of Ethernet (registered trademark)) to which a transmission source is connected. On the other hand, it is not transmitted to other network segments connected via the router.
The directed broadcast address is an IP address in which all bits of the host address part are set to 1 without changing the network address part. For example, for a network address of “192.168.8.0” in IPv4, “192.168.0.255” in which the host address part (lower 8 bits) is all 1 is the directed broadcast address. . When broadcast communication is performed by specifying a directed broadcast address, a key packet is transmitted to all computers 30 having a specific network address (“192.168.8.0” in the above example).

The communication trail management AP 22 is an application program for causing the communication management server 11 to execute a part of processing shown in FIG.
The control unit 31 of the communication management server 11 stores a communication trail log of the local terminal 15 (remote terminal 16) or the like by executing the communication trail management AP 22.

  The business server 12 is a server for realizing each business performed by a company or the like. The business server 12 executes response processing in response to a request from the local terminal 15 (remote terminal 16). In addition, the business server 12 may execute a predetermined batch process at a predetermined time.

In the VPN server 14, a key packet reception AP 23, a VPN connection AP 24, and the like are installed.
The key packet reception AP 23 is an application program for causing the VPN server 14, the local terminal 15 (remote terminal 16), and the like to execute processing shown in FIG.
The control unit 31 of the VPN server 14 receives information broadcast to the internal network 4 by executing the key packet reception AP 23. Further, the control unit 31 such as the VPN server 14 sets the reception flag stored in the RAM or the like to “Y” (reception) or “N” (reception) based on whether or not the key packet is received from the communication management server 11. None).

The VPN connection AP 24 is an application program for causing the VPN server 14 to execute server side processing in VPN connection and a part of processing shown in FIG.
The control unit 31 of the VPN server 14 performs server-side processing in the VPN connection by executing the VPN connection AP 24. Further, the control unit 31 of the VPN server 14 determines whether or not it is physically connected to the internal network 4 based on the reception flag stored in the RAM or the like. In addition, when the VPN connection is established from the remote terminal 16, the control unit 31 of the VPN server 14 transmits a determination result as to whether or not it is connected to the internal network 4 to the remote terminal 16.

In the local terminal 15 (remote terminal 16), a key packet receiving AP 23, a connection destination restricted AP 25, and the like are installed.
The key packet reception AP 23 is as described above. That is, the control unit 31 of the local terminal 15 (remote terminal 16) receives the information broadcast to the internal network 4 by executing the key packet reception AP 23. Further, the control unit 31 of the local terminal 15 (remote terminal 16) sets the reception flag stored in the RAM or the like to “Y” or “N” based on whether or not the key packet is received from the communication management server 11. To do.

The connection destination restriction AP 25 is an application program for causing the local terminal 15 (remote terminal 16) to execute the client side processing in the VPN connection and a part of the processing shown in FIG.
Whether the control unit 31 of the local terminal 15 (remote terminal 16) is physically connected to the internal network 4 based on the reception flag stored in the RAM or the like by executing the connection destination restriction AP 25 Determine whether or not. Further, when it is determined that the control unit 31 of the local terminal 15 (remote terminal 16) is physically connected to the internal network 4, the control unit 31 executes connection processing in response to a logical connection request. .

  On the other hand, when it is determined that the control unit 31 of the local terminal 15 (remote terminal 16) is not physically connected to the internal network 4, the control unit 31 performs VPN connection to the VPN server 14. Further, the control unit 31 of the local terminal 15 (remote terminal 16) is valid based on the determination result (received from the VPN server 14) whether the VPN server 14 is physically connected to the internal network 4 or not. It is determined whether or not it is connected to the VPN server 14. When it is determined that the local terminal 15 (remote terminal 16) is connected to the valid VPN server 14, the control unit 31 executes a connection process in response to a logical connection request.

FIG. 3 is a diagram illustrating a configuration of the connection destination restriction AP 25.
The connection destination restriction AP 25 includes an IP address 41 of the VPN server, a port number 42 of the VPN server, a connection determination program 43, a socket API (Application Programming Interface) 44, and the like. The IP address 41 of the VPN server and the port number 42 of the VPN server are stored, for example, in a setting file that can be read and written only by the administrator.

  The connection determination program 43 performs a process for determining whether or not the logical connection request of the local terminal 15 (remote terminal 16) may be permitted (a part of the process shown in FIG. 6 to be described later). This program is executed by the remote terminal 16).

The socket API 44 is a library related to a computer network that enables communication between computers 30 and communication between processes on one computer 30.
For example, in the case of TCP communication that is connection-type communication, the control unit 31 of the computer 30 that is a TCP client normally calls the socket function of the socket API 44 to generate a TCP socket, and the logical connection destination is the argument of the connect function. By specifying the address information (IP address and port number), communication with the connection destination is started. The logical connection destination is a computer 30 that is a TCP server.

Here, the local terminal 15 (remote terminal 16) in which the connection destination restriction AP 25 is installed always responds to a logical connection request from another program (for example, a device driver of a network adapter). It is desirable to have a mechanism in which 43 responds.
By this mechanism, even if a user who uses the remote terminal 16 outside the company 3 tries to cheat using a network adapter different from that instructed by the administrator, the connection determination process by the connection destination restriction AP 25 is avoided. It is not possible.

In order to realize the above-described mechanism, for example, the connection determination program 43 describes a wrap function of each function included in the socket API 44. In addition, the wrap function of the connection determination program 43 is set to be executed when a socket function or a connect function is called from another program. In the wrap function of the connection determination program 43, when VPN connection is executed as a result of the connection determination process, the logical connection destination address information set as an argument by another program is discarded and defined in advance. The IP address 41 of the VPN server and the port number 42 of the VPN server are set as arguments and each function included in the normal socket API 44 is called.
Accordingly, the computer 30 in which the connection destination restriction AP 25 is installed accesses only a predetermined single VPN server 14 when performing the VPN connection.
Further, in the connection determination program 43, when not physically connected to the internal network 4, applications other than the connection destination restricted AP 25 have the VPN server IP address 41 and the VPN server port number 42 defined in advance. It also includes a function for preventing VPN connection using. This prevents an unauthorized application from performing unauthorized communication using the IP address 41 of the VPN server and the port number 42 of the VPN server.

  When the connection destination restriction system 1 is actually operated, for example, the connection destination restriction AP 25 itself is stored as an OS in an external storage device, and when the local terminal 15 (remote terminal 16) is powered on, the external storage device A method is conceivable in which the OS (= connection destination restriction AP 25) stored in is set to be activated.

Returning to the description of FIG.
The external server 17 is a WWW (World Wide Web) server on the Internet. The external server 17 executes response processing in response to an HTTP (HyperText Transfer Protocol) request from the local terminal 15 (remote terminal 16) or the like, and returns an HTTP response.

Next, details of processing in the connection destination restriction system 1 will be described with reference to FIGS.
For example, the processes shown in FIGS. 5 and 6 (part of FIG. 6) are executed by the local terminal 15 (remote terminal 16). Therefore, the local terminal 15 (remote terminal 16) executes both processes almost simultaneously by multitasking (an OS mechanism that divides the CPU processing time into short units and makes it appear that multiple processes are performed simultaneously). To do. Other processes executed by a single device and overlapped in time series are similarly realized by multitasking.

FIG. 4 is a flowchart showing processing realized by the key packet transmission AP 21. The key packet transmission AP 21 is executed by the communication management server 11.
The control unit 31 of the communication management server 11 broadcasts a key packet to the internal network 4 (S101). Then, the control unit 31 of the communication management server 11 waits for a predetermined time (S102) and repeats the process of S101.

FIG. 5 is a flowchart showing processing realized by the key packet reception AP 23. The key packet reception AP 23 is executed by the VPN server 14 and the local terminal 15 (remote terminal 16).
The control unit 31 of the VPN server 14 and the local terminal 15 (remote terminal 16) monitors the key packet (S201) and checks whether the key packet is received within a predetermined time (S202).

  When the key packet is received within the predetermined time (“Yes” in S202), the control unit 31 of the VPN server 14 and the local terminal 15 (remote terminal 16) sets its reception flag stored in the RAM or the like to “Y ”(S203) and repeat from S201.

  On the other hand, when the key packet is not received within the predetermined time (“No” in S202), the control unit 31 of the VPN server 14 and the local terminal 15 (remote terminal 16) receives its own stored in the RAM or the like. The flag is set to “N” (S204), a forced disconnection process for forcibly disconnecting the connected communication by an interrupt is executed (S205), and the process is repeated from S201.

  4 and 5, the VPN server 14 and the local terminal 15 that are physically connected to the internal network 4 periodically receive key packets and are physically connected to the internal network 4. It can be determined that

FIG. 6 is a flowchart showing processing realized by the connection destination restricted AP 25 and the VPN connection AP 24. The connection destination restriction AP 25 is executed by the local terminal 15 (remote terminal 16). The VPN connection AP 24 is executed by the VPN server 14.
When the control unit 31 of the local terminal 15 (remote terminal 16) receives a logical connection request by a user operation or the like (S301), the control unit 31 checks a reception flag stored in its own RAM (S302).

  When the own reception flag is “Y” (“Y” in S302), the control unit 31 of the local terminal 15 (remote terminal 16) determines that it is physically connected to the internal network 4 and performs logical In response to a typical connection request, the connection process is executed as it is (S303), and the process ends.

  When its own reception flag is “N” (“N” in S302), the control unit 31 of the local terminal 15 (remote terminal 16) determines that it is not physically connected to the internal network 4, and VPN A connection request is transmitted to the VPN server 14 (S304). Here, as described above, the control unit 31 of the local terminal 15 (remote terminal 16) accesses the single VPN server 14 determined in advance.

The control unit 31 of the VPN server 14 transmits the reception flag stored in its own RAM or the like to the local terminal 15 (remote terminal 16) (S305).
The control unit 31 of the local terminal 15 (remote terminal 16) confirms the reception flag of the VPN server 14 (S306).

  When the reception flag of the VPN server 14 is “Y” (“Y” in S306), the control unit 31 of the local terminal 15 (remote terminal 16) determines that it is connected to the legitimate VPN server 14, and continues to the VPN. A connection process is executed (S307), and the process ends.

On the other hand, when the reception flag of the VPN server 14 is “N” (“N” in S306), the control unit 31 of the local terminal 15 (remote terminal 16) determines that it is not connected to the legitimate VPN server 14, Error processing is executed (S308), and the processing is terminated.
In the error processing in S308, the control unit 31 of the local terminal 15 (remote terminal 16) indicates, for example, that it is not physically connected to the internal network 4 and that it is not connected to the valid VPN server 14. The message is displayed on the display unit 34.

  The processing shown in FIG. 6 can prevent the terminal from being logically directly connected to the external server 17 or the like. In the case of the local terminal 15 (when the terminal is physically connected to the internal network 4), since the connection process is executed as it is, it is logically directly connected to the business server 12 and the like installed in the internal network 4. Can be connected. Further, in the case of the remote terminal 16 (when the terminal is physically connected to the external network 5), the VPN connection process is executed, so that the connection to the external server 17 or the like is always made via the VPN server 14. it can.

  FIG. 7 is a flowchart showing processing realized by the communication trail management AP 22. The communication trail management AP 22 is executed by the communication management server 11.

FIG. 7 shows a process in the case of an HTTP request to the external server 17 as an example of a logical connection request.
As a premise of the process shown in FIG. 7, it is assumed that the local terminal 15 (remote terminal 16) is executing the connection process (VPN connection process) shown in FIG. All logical connection requests by the local terminal 15 (remote terminal 16) are transmitted to the external server 17 via the communication management server 11.

  In the case of the remote terminal 16, the VPN server 14 is routed before the communication management server 11. In order to make the explanation regarding the communication trail log acquisition process easier to understand, FIG. 7 shows the relay process of the VPN server 14. Is omitted. In the case of the remote terminal 16, the VPN server 14 may substitute the processing of the communication management server 11.

The control unit 31 of the local terminal 15 (remote terminal 16) transmits an HTTP request to the communication management server 11 (S401). In the case of the remote terminal 16, the HTTP request is always transmitted via the VPN server 14.
The control unit 31 of the communication management server 11 stores the communication trail log (S402), and transmits an HTTP request to the external server 17 (S403).

The control unit 31 of the external server 17 executes an HTTP request response process (S404), and transmits an HTTP response to the communication management server 11 (S405).
The control unit 31 of the communication management server 11 stores the communication trail log (S406), and transmits an HTTP response to the local terminal 15 (remote terminal 16) (S407). In the case of the remote terminal 16, the HTTP response is always transmitted via the VPN server 14.
The control unit 31 of the local terminal 15 (remote terminal 16) displays a screen on the display unit 34 based on the HTTP response (S408).

  With the processing shown in FIG. 7, all the communication trail logs of the local terminal 15 and the remote terminal 16 can be managed in an integrated manner. Then, by telling the user that all communication trail logs have been acquired regardless of whether they are in the company 2 or outside the company 3, intentional information leakage can be suppressed.

  In the example shown in FIG. 7, the communication management server 11 performs only the process of acquiring the communication trail log. Further, the communication management server 11 detects the access restriction of the website on the Internet and the detection of the update omission of the pattern file of the anti-virus software. It can also be done. This can reduce the security risk for the terminal.

  According to the connection destination restriction system 1 of the present invention, a terminal can be prevented from being logically directly connected to an external server or the like. As a result, it is possible to improve the situation where the security risk for the terminal is high and the situation where it is easy to intentionally leak information.

  The preferred embodiments of the connection destination restriction system and the like according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.

1 ......... Connection Destination Restriction System 4 ......... Internal Network 5 ......... External Network 11 ......... Communication Management Server 12 ......... Business Server 13 ......... Firewall 14 ......... VPN Server 15 ......... Local Terminal 16: Remote terminal 17: External server 21: Key packet transmission AP
22 …… Communication trail management AP
23 ... Key packet receiving AP
24 ... VPN connection AP
25 ……… Access restriction AP

Claims (4)

A connection destination restriction system that includes a terminal physically connected to an internal network and an external network, and a communication management server physically connected to the internal network, and restricts a logical connection destination of the terminal. ,
The communication management server
Broadcast transmission means for intermittently transmitting permission information indicating permission of a logical connection request of the terminal to the internal network,
Comprising
The terminal
First broadcast receiving means for receiving information broadcast to the internal network;
First determination means for determining that the first broadcast receiving means is physically connected to the internal network when the permission information is received by the first broadcast receiving means;
If the first determination means determines that it is physically connected to the internal network, the first connection means executes connection processing in response to the logical connection request;
A connection destination restriction system comprising: The connection destination restriction system further includes a VPN server physically connected to the internal network,
The VPN server is
Second broadcast receiving means for receiving information broadcast to the internal network;
When the permission information is received by the second broadcast receiving means, second determining means for determining that the second broadcast receiving means is physically connected to the internal network;
When a VPN connection request is received from the terminal, a transmission unit that transmits a determination result by the second determination unit to the terminal;
Comprising
The terminal
If the first determination means determines that it is not physically connected to the internal network, the VPN connection request is transmitted to the VPN server, and the VPN server further transmits the VPN server. Receiving a determination result indicating that the network is physically connected to the internal network, third determination means for determining that the network is connected to the valid VPN server;
A second connection unit that executes VPN connection processing in response to the logical connection request when the third determination unit determines that it is connected to the valid VPN server;
The connection destination restriction system according to claim 1, further comprising: The first connection means and the second connection means always respond to the logical connection request,
3. The connection restriction system according to claim 2, wherein the third determination unit performs the VPN connection only by using address information of the VPN server stored in advance in the terminal. Connection destination in a connection destination restriction system that has a terminal physically connected to the internal network and the external network, and a communication management server physically connected to the internal network, and restricts a logical connection destination of the terminal Restriction method,
A first step in which the communication management server intermittently broadcasts permission information indicating permission of the logical connection request of the terminal to the internal network;
A second step for the terminal to receive information broadcast to the internal network;
A third step of determining that the terminal is physically connected to the internal network when the terminal receives the permission information in the second step;
If the terminal determines that it is physically connected to the internal network in the third step, a fourth step of executing connection processing in response to the logical connection request;
A connection destination limiting method comprising:

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