KR20180009908A - Method for indirect connectivity using local network server in network-seperated environment, recording medium and system for performing the method - Google Patents

Abstract

An indirect interworking method through an internal network transmission control server in a network separation environment includes a step of receiving, from the external network transmission control server, a full text of a NoSQL (Non-Structured Query Language) ; Converting the received NoSQL method specification into a SQL (Structured Query Language) method; Processing DB inquiry according to a policy of the internal network, generating result data as a file, and transmitting the file to the external network transmission control server; And storing the file received from the external network transmission control server in a designated directory and terminating the process. Accordingly, the DB information, the connection information, and the SQL information are not left in the Internet network, and the security of the internal network can be improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indirect interworking method using an internal network transmission control server in a network separation environment, a recording medium and a system for performing the indirect interworking method,

The present invention relates to an indirect interworking method using an internal network transmission control server in a network separation environment, a recording medium and a system for performing the indirect interworking method, and more particularly, To an indirect interlocking method for increasing the interlocking speed.

Network separation refers to separating the internal network (network) and the external network to prevent intrusion from outside and to prevent leakage of internal information. These network separation methods include direct linking and indirect linking.

Direct interworking is an interworking way in which data is communicated in both directions in which the server responds to a service or data request. Directly requesting unspecified SQL from the Internet network to obtain a desired result, or directly calling a Web service (URL input) using the port 80 in the Internet network and obtaining the result, corresponds to a direct linking method .

Indirect interworking is a one-way communication in the form of file transmission and an interworking method of terminating. It transmits the log generated by the Internet server to the defense network server and does not have a response. It is an interworking method in which the request and response are programmed in the form of an API and only the promised data is transmitted and received between the two parties. In addition, the Yes / No signal corresponds to the indirect interworking method such as the health check in the response contents of the two-way communication system.

Comparing the advantages and disadvantages of direct interworking method and indirect interworking method, direct interworking method transmits data to existing protocol, whereas indirect interworking method generates and transmits data by file unit. In terms of security, there is a protocol vulnerability in the direct link method, but there is no known vulnerability in the indirect link method because the protocol is changed.

In the session side, the direct interworking method is composed of separate TCP / IP sessions inside and outside, but the entire section is linked to one L7 session, while the indirect interworking method consists of separate TCP / IP sessions inside and outside, and there is an L7 session I never do that. In terms of transmission performance, the direct interworking method can transmit data in real time (real time data such as CCTV), while the indirect interworking method can not transmit in real time (except some interconnection). In the aspect of malicious code inspection, direct interlocking method is difficult to real-time monitoring, while indirect interlocking method can be processed in case of file inspection and malicious code infection.

In terms of application method, direct interworking method can be applied by changing IP setting (applicable without changing existing application), whereas indirect interworking method is applicable only when application is modified System development considering). Therefore, in terms of cost, the direct interworking method requires the cost of constructing the data exchange system, but the indirect interworking method requires application customization cost in addition to the data exchange system construction cost.

Accordingly, the task using the network linkage system can be operated only indirectly. In recent years, although the network separation business has progressed much, when the direct interworking method is used, the server interlocks data communication in two directions for the data request. Therefore, even if the network is separated, There is no change. Therefore, the vulnerabilities of existing protocols are equally vulnerable in network separation environments. Also, it is difficult to grasp the data flow history accurately only by protocol analysis.

In addition, if the data transmission request of the existing protocol is blocked, the program may fail, and it is difficult to implement the filtering function of the external influent data such as the malicious code inspection.

KR 10-1425726 B1 KR 10-1472685 B1

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an indirect interworking method through an internal network transmission control server in a network separation environment for improving security.

It is another object of the present invention to provide a recording medium on which a computer program for performing an indirect interworking method through an internal network transmission control server in the network separation environment is recorded.

It is still another object of the present invention to provide a system for performing an indirect interworking method in the network separation environment.

The indirect interworking method through the internal network transmission control server in the network separation environment according to an embodiment for realizing the above-described present invention is characterized in that when there is a data inquiry request from a client, a non-structured query language (NoSQL) Receiving, on a file-by-file basis, a message from the external network transmission control server; Converting the received NoSQL method specification into a SQL (Structured Query Language) method; Processing DB inquiry according to a policy of the internal network, generating result data as a file, and transmitting the file to the external network transmission control server; And storing the file received from the external network transmission control server in a designated directory and terminating the process.

In an embodiment of the present invention, an indirect interworking method using an internal network transmission control server in the network separation environment includes: checking if the data is a predetermined type of data when a transmission request is made from the internal network to the external network; And transmitting the data to the external network only when the corresponding data is a predetermined type of data.

In an embodiment of the present invention, the indirect interworking method through the internal network transmission control server in the network separation environment may further include generating a log for data transmitted to the external network to perform an audit function.

In the embodiment of the present invention, the indirect interworking method through the internal network transmission control server in the network separation environment includes masking the data transmitted to the external network and providing an exposure blocking function of the specified data .

In the embodiment of the present invention, when receiving a data inquiry request from the client, the step of receiving a message of a non-structured query language (NoSQL) method from the external network transmission control server in units of files is performed by the WAS server Protocol can be received.

In an embodiment of the present invention, the indirect interworking method through the internal network transfer control server in the network separation environment may further include checking the authority of the received NoSQL method specialization.

In an embodiment of the present invention, the indirect interworking method through the internal network transmission control server in the network separation environment may further include performing malicious code checking on data transmitted from the external network.

According to another aspect of the present invention, there is provided a computer readable storage medium storing a computer program for performing an indirect interworking method using an internal network transmission control server in a network separation environment.

According to another aspect of the present invention, there is provided an indirect interworking system in a network separation environment, wherein when a client requests a data query, a non-structured query language (NoSQL) Dedicated drivers to generate specialists; An external network transmission control server for transmitting the NoSQL type message received from the dedicated driver; And a NoSQL method specification transmitted from the external network transmission control server on a file unit basis. If the received NoSQL method special authority is confirmed, the received NoSQL method specification is converted into a Structured Query Language And transmits the generated data to the external network transmission control server. The internal network transmission control server stores the file received from the external network transmission control server in the designated directory. And a control server.

According to another aspect of the present invention, there is provided an indirect interworking system in a network separation environment, comprising: a collection server for uploading a mail received from a terminal of an external network and transmitting the received mail through a specific protocol; An external network transmission control server for receiving a mail from the collection server through a specific protocol and transmitting the transmission result to the collection server; And an internal network transmission control server for forming the original text of the mail delivered from the external network transmission control server into a file and delivering it to the destination server of the internal network through the internal transmission protocol when the settlement is completed according to the policy of the internal network .

In the embodiment of the present invention, the specific protocol is HTTP (Hypertext Transfer Protocol) put, and the external network transmission control server can transmit the 200 OK transmission result to the collection server.

In the embodiment of the present invention, the specific protocol is SMTP (Simple Mail Transfer Protocol), and the external network transmission control server can transmit a response message to the collection server when the response of the internal transmission control server is completed.

According to another aspect of the present invention, there is provided an indirect interworking system in a network separation environment, including: a standard time server for providing standard time; An external network transmission control server for synchronizing time based on the time of the standard time server and synchronizing time through NTP (Network Time Protocol) at regular intervals; And an internal network transmission control server for synchronizing time by the external network transmission control server and synchronizing time of servers of the internal network through an internal transmission protocol.

In an embodiment of the present invention, the indirectly interworking system in the network separation environment may further include storage for transferring a file transferred from the external network transmission control server to an internal network through a data exchange system.

In the embodiment of the present invention, when there is a transmission request from the internal network to the external network, the internal network transmission control server checks whether the corresponding data is a predetermined type of data, and if the corresponding data is a predetermined type of data Only to the external network.

In the exemplary embodiment of the present invention, the internal network transmission control server may include a function of generating a log of data transmitted to the external network, a function of masking data transmitted to the external network, And a function of performing malicious code checking on data transmitted from the external network.

According to the indirect linking method through the internal network transmission control server in such a network separation environment, when the internal DB data is retrieved from the external internet network, general information such as DB connection information or kind is used without using SQL in the Internet network Therefore, it is possible to block the execution of arbitrary SQL or the like against the internal DB and use only the target information. Accordingly, when referring to the data of the internal network in the external internet network in the network separation environment, the security of the internal network can be improved by not leaving DB information, connection information and SQL information in the Internet network.

1 is a diagram of an indirectly coupled system in a network separation environment according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an indirect interworking process in a network separation environment performed in the system of FIG. 1; FIG.
3 is a diagram showing an example of coding when using the dedicated driver of FIG.
4 is a diagram of an indirectly coupled system in a network separation environment according to another embodiment of the present invention.
5 is a diagram of an indirectly coupled system in a network separation environment according to another embodiment of the present invention.
FIG. 6 is a diagram illustrating an indirect interworking process in a network separation environment performed in the system of FIG. 5; FIG.
FIG. 7 is a diagram illustrating a network separation indirect interworking process according to another embodiment of the present invention.
8 is a diagram illustrating an indirect interworking process in a network separation environment according to another embodiment of the present invention.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

The indirect interworking method and system using the internal network transmission control server in the network separation environment according to the present invention does not store the SQL in the external network server without setting the database connection information in the external network server. In addition, standard SQL is not used for requests sent from the external network server, and data sent from the internal network to the external network only allows data of a predetermined type (Static SQL). In addition, it is possible to increase the security of the internal network by providing the audit function by generating the log of the leaked data.

Hereinafter, an indirect interworking method and system using an internal network transmission control server in a network separation environment according to specific embodiments of the present invention will be described.

1 is a diagram of an indirectly coupled system in a network separation environment according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an indirect interworking process in a network separation environment performed in the system of FIG. 1; FIG.

INDUSTRIAL APPLICABILITY According to the present invention, an indirectly interworking system (hereinafter, referred to as "system 1") is an interworking system in which an intrusion It improves security by preventing data leakage.

1 and 2, a system 1 according to the present invention includes a dedicated server 20, an external network transmission control server 30, and an internal network transmission control server 50 . The system 1 may further include a storage 40 for providing data exchange between the external network transmission control server 30 and the internal network transmission control server 50.

The indirect interworking according to the present embodiment is a database (DB) data interlocking method. In the case of searching internal DB data in the Internet network, general information such as DB connection information or kind is not used without using SQL in the Internet network . Accordingly, the execution of arbitrary SQL and the like is intercepted from the internal DB, and the function is implemented so that only the provided information can be used.

Specifically, the dedicated server 20 of the system 1 receives a request through the web server 10 when a user makes a data request through the Internet. At this time, the dedicated server 20 does not use DML, DDL, and standard driver such as standard SQL, and generates a specialist of NoSQL (Non-Structured Query Language) through a dedicated driver.

Therefore, the server in the external network area of the system 1 does not use the standard SQL, and DB type, DB connection information, and the like are not present in the Internet network server area. Accordingly, the DB type of the internal network can not be known from the outside, and the user account or DB-related setting information for connecting the DB of the internal network can not be known from the outside.

The dedicated server 20 transfers the created NoSQL method message to the external network transmission control server 30. The specialization of the NoSQL method is transmitted to the internal network transmission control server 50 through the data exchange system of the storage 40.

The internal network transmission control server 50 receives the special character of the NoSQL method on a file unit basis and confirms the received special character of the NoSQL method and verifies the received special character of the NoSQL method to SQL Query Language).

Also, the internal network transmission control server 50 processes the DB inquiry according to the policy of the internal network, and transmits the result data to a file (for example, a response message). The response message is transmitted to the external network transmission control server 30 through the data exchange system of the storage 40 and the external network transmission control server 30 transmits the response message back to the dedicated server 20 do.

Meanwhile, the internal network transmission control server 50 stores the file received from the external network transmission control server 30 through the internal transmission protocol in a designated directory of the internal DB server 60, and ends the process. In addition, security can be strengthened by providing privilege management function for externally requested data sets and malicious code checking function for externally transmitted data.

If there is a transmission request from the internal network to the external network, the internal network transmission control server 50 checks whether the corresponding data is a predetermined type of data, and if the corresponding data is a predetermined type (Static SQL) , And transmits it to the external network.

Also, by providing a function to block data other than the data set of the providing type from the Internet, it is possible to provide one level higher security function than DB access control. It can provide detailed audit function for outgoing data or generate a log or masking the outgoing data to provide a function of blocking exposure of sensitive data such as personal information.

FIG. 3A shows a coding example when using an existing driver, and FIG. 3B shows an example of coding when a dedicated driver is used according to the present invention.

Referring to FIG. 3A, when using the standard Oracle driver, the DB connection information of the internal network is present in the program or configuration information, and the DB connection ID and password of the internal network are set. Accordingly, DB type and DB connection information of the internal network are left in the external network even in the network separation environment, which is vulnerable to security.

Referring to FIG. 3B, in the present invention, only the ID and password for accessing the information and data exchange system of the external network transmission control server are registered because the network connection dedicated driver is used. Accordingly, the DB type of the internal network can not be known from the outside, and the user account for connecting the DB of the internal network and the DB-related setting information can not be known from the outside, thereby improving the security.

4 is a diagram of an indirectly coupled system in a network separation environment according to another embodiment of the present invention.

Referring to FIG. 4, the system 2 according to the present invention includes an external network transmission control server 32 and an internal network transmission control server 52. The system 2 may further include a storage 42 for providing data exchange between the external network transmission control server 32 and the internal network transmission control server 52.

The indirect interworking according to the present embodiment is a file-based interworking method. In the data interchange system, when a data interchange function between an internal network and an Internet network is implemented, a file name or a special name is designated and transmitted to a file unit or a specialized unit. (52) implements the function of transmitting manganese data through malicious code inspection and approval according to the type of the special number or file name.

Specifically, in the system 2, when a user (client) 62 of the internal network generates and transmits data to be transmitted to the server 12 in the external area as a file, the generated file is transmitted through TCP (Transmission Control Protocol) To the internal network transmission control server (52).

The internal network transmission control server 52 proceeds to the malicious code inspection of the received file and the approval process according to the policy, and after the internal process is completed, the internal network transmission control server 52 can export the file to the outside by the external transfer service.

The external network transmission control server 32 acquires the file received from the internal network using the policy information and transmits the file to the reception server 12. The receiving server 12 stores the file received from the external network transmission control server 32 in a designated directory and terminates the process.

In this embodiment, the internal network and the external network program can transmit a file by using a file transfer protocol such as API or FTP for transmitting data.

5 is a diagram of an indirectly coupled system in a network separation environment according to another embodiment of the present invention. FIG. 6 is a diagram illustrating an indirect interworking process in a network separation environment performed in the system of FIG. 5; FIG.

Referring to FIGS. 5 and 6, the system 3 includes a collection server 23, an external network transmission control server 33, and an internal network transmission control server 53. The system 3 may further comprise a storage 43 for providing data exchange between the external network transmission control server 33 and the internal network transmission control server 53.

The indirect interworking according to this embodiment is a unidirectional linking method of HTTP (Hyper Text Transfer Protocol). When data is transferred from the Internet network to the internal network, the file is transmitted using the HTTP protocol, the received file is stored, After the processing, the file is transferred to the target server according to the policy. In addition, the response message to the Internet network server only reports the result such as 200 OK.

Specifically, the system 3 uploads data to the collection server 23 from a terminal such as a smart phone or a PC in the external network. For example, a user can compose and send a mail.

The collection server 23 transmits the content to the external network transmission control server 33 via HTTP put. The external network transmission control server 33 transmits only the transmission result such as 200 OK to the collection server 23.

The data transmitted to the external network transmission control server 33 is transmitted to the internal network transmission control server 53 through a data exchange system. The internal network transmission control server 53 generates a received mail text as a file, executes a malicious code check through a vaccine on the received mail, and proceeds with the settlement process according to the policy.

Thereafter, the internal network transmission control server 53 transmits the data to the destination server 63 through the HTTP put to the file in which the import procedure is completed.

FIG. 7 is a diagram illustrating a network separation indirect interworking process according to another embodiment of the present invention.

Referring to FIG. 7, the system 4 includes a collection server 24, an external network transmission control server 34, and an internal network transmission control server 54. The system 4 may further include a storage 44 for providing data exchange between the external network transmission control server 34 and the internal network transmission control server 54.

The indirect interworking according to the present embodiment is an SMTP (Simple Mail Transfer Protocol) -based interworking method, and implements functions such as file and notify via the SMTP protocol when transferring data from the Internet network to the internal network.

The present embodiment converts data collected through the SMTP protocol into eml and performs malicious code checking. In addition, according to the internal policy, transmission or blocking is performed to the receiver and the transmission history is left.

Specifically, in the system 4, a mail client (Client) 24 sends a mail to the external network transmission control server 34 (SMTP Request). The external network transmission control server 34 transfers the received file to the internal network transmission control server 54 via the storage 44.

The internal network transmission control server 54 generates the received mail text as a file, receives the mail sent via SMTP, and executes a response. The internal network transmission control server 54 transmits a response message to the external network transmission control server 34 and the external network transmission control server 34 transmits the message to the mail client 24 And transmits the result.

The internal network transmission control server 54 executes a malicious code check through a vaccine on the received mail and performs a settlement process through the payment system according to the internal policy. In addition, after the internal processing process is completed, the data is transmitted to the target server 64.

8 is a diagram illustrating an indirect interworking process in a network separation environment according to another embodiment of the present invention.

Referring to FIG. 8, the system 5 includes a standard time server 25 that provides standard time, an external network transmission control server 35, and an internal network transmission control server 55. The system 5 may further include a storage 45 for providing data exchange between the external network transmission control server 35 and the internal network transmission control server 55.

The indirect interworking according to this embodiment is an NTP (Network Time Protocol) protocol interworking method, and the Internet network server periodically performs time synchronization with an external time server. The Internet network server and the business network server periodically synchronize with each other, and the server operating in the business network synchronizes the time through the time synchronization with the business network transmission control server.

In the system 5, the external network transmission control server 35 synchronizes the time with the standard time provided by the standard time server 25 and transmits the external network transmission control server 35, And the internal network transmission control server (55).

The internal network transmission control server 55 synchronizes the time of the internal network servers with the external network time with the NTP service. As a result, security can be enhanced by clarifying data receiving time and transmission time of the internal network.

The indirect interworking method using the internal network transmission control server in the network separation environment according to the present invention may be implemented in the form of an application program or a program instruction that can be executed through various computer components, Lt; / RTI > The computer-readable recording medium may include program commands, data files, data structures, and the like, alone or in combination.

The program instructions recorded on the computer-readable recording medium may be ones that are specially designed and configured for the present invention and are known and available to those skilled in the art of computer software.

Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like.

Examples of program instructions include machine language code such as those generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules for performing the processing according to the present invention, and vice versa.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. You will understand.

Since the present invention uses a self-developed driver instead of a standard driver in a separate environment between an internal business network and an external Internet network, SQL is not stored without setting database connection information in an external network server. Therefore, it can be applied to the indirect interworking method in the widely used network separation environment, thereby enhancing the security of DB access of the internal network.

1, 2, 3, 4, 5: Indirect interlocking system
10, 12: Web server
20: dedicated server
23, 24: collection server
25: Standard Time Server
30, 32, 33, 34, 35: external network transmission control server
40, 42, 43, 44, 45: storage
50, 52, 53, 54, 55: internal network transmission control server
60, 62, 63, 64, 65: internal server

Claims (16)

In an indirect interworking method through an internal network transmission control server in a network separation environment,
Receiving, in a file unit, a message of a non-structured query language (NoSQL) method from an external network transmission control server when a client requests a data inquiry;
Converting the received NoSQL method specification into a SQL (Structured Query Language) method;
Processing DB inquiry according to a policy of the internal network, generating result data as a file, and transmitting the file to the external network transmission control server; And
Storing the file received from the external network transmission control server in a designated directory and terminating the process; and indirectly interworking through the internal network transmission control server in the network separation environment.
The method according to claim 1,
Confirming whether the data is a predetermined type of data when there is a transmission request from the internal network to the external network; And
And transmitting the data to the external network only when the corresponding data is a predetermined type of data. The indirect interworking method using an internal network transmission control server in a network separation environment.
3. The method of claim 2,
The method of claim 1, further comprising: generating a log for data transmitted to the external network to perform an auditing function, wherein the indirect interworking method through the internal network transmission control server in the network separation environment.
3. The method of claim 2,
The method of claim 1, further comprising masking data transmitted to an external network to provide a function of blocking exposure of the specified data.
The method as claimed in claim 1, wherein, in the case where there is a data inquiry request from the client, the step of receiving, from the external network transmission control server,
An indirect interworking method through an internal network transmission control server in a network separation environment, receiving a data inquiry request from a WAS server through a dedicated protocol.
The method according to claim 1,
Further comprising the step of verifying the authority of the received NoSQL method special clause, in the network separation environment.
The method according to claim 1,
And performing malicious code checking on data transmitted from an external network, wherein the indirect interworking method via the internal network transmission control server in the network separation environment.
A computer-readable recording medium on which a computer program is recorded for performing a method of indirectly connecting via an internal network transmission control server in a network separation environment according to any one of claims 1 to 7.
A dedicated driver for generating a special case of a non-structured query language (NoSQL) method through a dedicated protocol when there is a data inquiry request from a client;
An external network transmission control server for transmitting the NoSQL type message received from the dedicated driver; And
The method comprising the steps of: receiving, in a unit of a file, a special character of the NoSQL method transmitted from the external network transmission control server; and converting the received special character of the NoSQL method into a Structured Query Language And transmits the data to the external network transmission control server. In addition, the internal network transmission control server stores the file received from the external network transmission control server in a designated directory, An indirectly coupled system in a networked environment, including a server.
A collection server for uploading a mail received from a terminal of an external network and transmitting the received mail through a specific protocol;
An external network transmission control server for receiving a mail from the collection server through a specific protocol and transmitting the transmission result to the collection server; And
And an internal network transmission control server for forming the original text of the mail delivered from the external network transmission control server into a file and delivering it to the destination server of the internal network through an internal transmission protocol when the settlement is completed according to the policy of the internal network. Indirect Interworking System in Network Separation Environment.
11. The method of claim 10,
Wherein the specific protocol is an HTTP (Hypertext Transfer Protocol) put, and the external network transmission control server transmits a 200 OK transmission result to the collection server.
11. The method of claim 10,
Wherein the specific protocol is a Simple Mail Transfer Protocol (SMTP), and the external network transmission control server transmits a response message to the collection server when the response of the internal transmission control server is completed.
A standard time server providing standard time;
An external network transmission control server for synchronizing time based on the time of the standard time server and synchronizing time through NTP (Network Time Protocol) at regular intervals; And
An internal network transmission control server synchronizing time by the external network transmission control server and synchronizing time of servers of the internal network through an internal transmission protocol.
14. The method according to any one of claims 9 to 13,
And a storage for transferring the file transferred from the external network transmission control server to the internal network through a data exchange system.
14. The internal network transmission control server according to any one of claims 9 to 13,
If there is a transmission request from the internal network to the external network, it is checked whether the data is a predetermined type of data, and if the data is a predetermined type of data, the data is transmitted to the external network. system.
14. The internal network transmission control server according to any one of claims 9 to 13,
A function to generate logs for data transmitted to the external network, a function to mask exposure of specified data by masking the data transmitted to the external network, and a malicious code inspection to the data transmitted from the external network A function of at least one of security functions of the network.

Images