KR20050078325A - Tcp packet communication method and system for private ip terminals - Google Patents

Abstract

The present invention provides a method for establishing a TCP channel from a public IP communication terminal device to a private IP communication terminal device in the Internet in which a communication terminal device using a private IP (Internet Protocol) address and a communication terminal device using a public IP address are connected. Method of establishing a TCP channel between a communication terminal device using a private IP address of a different network, and having a router map an internal private IP address and a port with the router's port information. By using the public IP as a method, and the relay server to transfer the information of different communication terminal devices to each other to enable the bidirectional TCP packet transmission between the communication terminal devices. The method of the present invention comprises the steps of: private IP terminals registering a private IP address-approved IP address and port with a TCP relay server; A second step of obtaining, by the calling private IP terminal requiring TCP communication, the public IP address and port information of the called private IP terminal from the TCP relay server; A third step of attempting a TCP connection to the public IP address and port by the calling private IP terminal having obtained the public IP address and port information of the incoming private IP terminal; And a fourth step in which the called private IP terminal establishes a TCP channel by receiving and responding to the TCP connection request.

Description

TCP packet communication method and system for a communication terminal device using a private IP {TCP packet communication method and system for private IP terminals}

The present invention relates to a packet communication technology using the Internet Protocol (IP), and more particularly, to a TCP protocol between private IP terminals on different private networks. It relates to a method and system for communication using.

In general, private IP addresses designed to solve the problem of depletion of limited Internet Protocol addresses as more and more users of the Internet and to allow more people to access the Internet are secure and load balancing. It is also widely used for additional effects such as However, these private IP addresses are redundantly used by many systems connected to the Internet and thus cannot be guaranteed uniqueness on the Internet. In other words, since duplicate IPs cannot be distinguished from each other and direct data transmission between each other is impossible, in the existing network, between communication terminal devices having public IP addresses or private IP communication terminals in the direction of public IP devices and inside the same private network. TCP connection was possible only between communication terminal devices.

Therefore, in the related art, there is a problem in that a connection setting from a public IP address terminal device to a private IP address terminal device or a TCP connection between terminal devices having private IP addresses located in different networks is impossible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and can perform TCP communication between private IP terminal devices of different networks using a network address translation (NAT) and a relay server. It is an object of the present invention to provide a method and system for establishing a TCP connection between communication terminal devices using a private IP.

In order to achieve the above object, a method of the present invention includes a first step of registering private IP address-approved IP address information in a TCP relay server by private IP terminals; A second step of obtaining, by the originating private IP terminal requiring TCP communication, the public IP address of the called private IP terminal from the TCP relay server; A third step of requesting a TCP d connection to a public IP address by a calling private IP terminal having obtained the public IP address of the called private IP terminal; And a fourth step in which the called private IP terminal accepts the TCP connection request, establishes a TCP channel with each other, and then transmits and receives data like a conventional TCP connection.

In addition, to achieve the above object, the system of the present invention includes a first private IP terminal using a first private IP belonging to the first network; A first network address translator for mapping the first private IP to a first public IP; A second private IP terminal belonging to the second network and using a second private IP; A second network address translator for mapping the second private IP to a second public IP; And a TCP relay server which maintains TCP channel information for TCP communication between the private IP terminals belonging to different networks.

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

[Concept of invention]

1 is a schematic diagram illustrating a concept of communicating using a private IP according to the present invention, wherein (a) is a private IP terminal 110-1 belonging to the private network 102 belonging to another private network 104; The IP terminal 110-2 communicates with the user through a TCP channel, and (b) the public IP terminal 120 of the real IP network 106 is connected to the private IP terminal 110-1 of the private IP network 102. Direction to establish and communicate a TCP channel connection. In other words, in the conventional communication environment such as (a) and (b) of FIG. 1, the TCP connection could not be established, but in the present invention, the NAT function of the TCP relay server and the router converts the private IP address into a public IP address. In the communication environment as shown in (a) and (b) of FIG. 1, the TCP connection is enabled.

[First Embodiment]

2 is an overall configuration diagram showing a TCP communication environment between private IP networks according to the present invention.

Referring to FIG. 2, a plurality of private IP terminals 110-1 using a private IP address are connected to the first private network 102 to communicate using a private IP address in an internal network 102. The router 210-1 of the private network 102 can connect with other public IP servers and terminals through the Internet 202 using a public IP address. In addition, a plurality of private IP terminals 110-2 using a private IP address are connected to the second private network 104, which is another private network, and communicates using the private IP address in the internal network 104. The router 210-2 of 104 may be connected to other public IP servers and terminals through the Internet 202 using a public IP address. Here, the private IP address is an IP address that is defined privately and guarantees uniqueness only in the private network. Unlike a public IP address, the private IP address is an IP address that does not guarantee uniqueness in the public network. Therefore, in order to use a private IP address in a public network, a network address translation (NAT) function for converting a private IP address into a public IP address is required. In the embodiment of the present invention, routers include a NAT function. Used as.

 In addition, a plurality of public IP terminals 220 or service servers may be connected to the Internet 202, and the TCP relay server 230 for allowing TCP communication using a private IP address according to the present invention may also be connected to the Internet 202. Is connected to.

In this communication environment, each server or terminal is assigned a unique IP address and communicates. In the case of a public IP address, it communicates in the format shown in Table 1 according to the IPv4 protocol specified by IETF.

According to the Internet protocol, as shown in Table 1, the IP packet has a source address, which is the sender's address, and a destination address, which is the recipient's address. For example, private IP addresses must be translated into public IP addresses before they can be delivered over an open network.

In the embodiment of the present invention, it is assumed that IP addresses assigned to each terminal and server shown in FIG. 2 are shown in Table 2 below.

  Terminal / Server Name   IP Type    IP address   Port number   Private IP1 Terminal   Private IP     IP # 1    $ 1   Router 1   Public IP     IP # 3    $ 3   Private IP2 Terminal   Private IP     IP # 2    $ 2   Router 2   Public IP     IP # 4    $ 4   Authorized IP Terminal   Public IP     IP # 7    $ 6   UDP relay server   Public IP     IP # 5    $ 5

In the embodiment of the present invention, as shown in Table 2, the IP number is displayed after "#", and the port number is displayed after "$". In general, since a network address translator (NAT) has a few public IP addresses, it uses public IP address and port information to connect (map) a plurality of private IP addresses to the outside.

FIG. 3 is a flowchart illustrating a process of establishing a TCP connection between two private IP terminals in different networks in the communication environment shown in FIG. 2.

Referring to FIG. 3, the TCP communication process between the first private IP terminal 110-1 of the first private network 102 and the second private IP terminal 110-2 of the second private network 104 is performed by a TCP relay server. A registration process of registering a 'private IP address: Port-authorized IP address: Port' pair of each private IP terminal at 230 and a TCP channel setting process of acquiring the public IP address information of the other party from the TCP relay server 230 The TCP flow is divided into TCP packet exchange processes and is shown as a signal flow between communication nodes. In the present invention, since the terminals of the private network use the private IP address, it is necessary to convert and manage the public IP address to ensure the uniqueness in the open network. To this end, routers 210-1 and 210-2 of each private network map a private IP address and a port to a port of a public IP address including a NAT function, and the TCP relay server 230 corresponds to the private IP addresses. It manages the relay table of public IP addresses so that public IP addresses can be found as private IP addresses. At this time, in order to classify private IP address, it must manage by mapping with ID system that guarantees uniqueness.

First, each of the private IP terminals 110-1 and 110-2 needs to register a public IP address corresponding to its private IP address in the relay table of the TCP relay server 230 at logon or periodically. To this end, the first private IP terminal 110-1 has a source address of its own private IP address and a port number (ie, private IP # 1- $ 1), and a destination address of the relay server 230. That is, it forms a TCP packet of public IP # 5- $ 5) and requests a TCP connection through the first router 210-1 (301-1).

The first router 210-1 receives a TCP packet from the terminal 110-1, and extracts a private IP address and a port number (private IP # 1-$ 1) information of a source from the received packet. At this time, the first router 210-1 allocates an extra external port (for example, $ 3) and assigns a private IP address and port number (private IP # 1- $ 1) and an external port ($ 3) of the internal terminal. It is stored in the mapping table as shown (302-1). Subsequently, the first router 210-1 changes the source address of the packet to its own public IP address (authorized IP # 3) and port ($ 3), so that the destination address of the packet (authorized IP # 5) is changed. -$ 5) retransmits the TCP connection request packet to the relay server 230 (303-1).

This process is similarly performed for the second private IP terminal 110-2 of another private network, and the second router 210-2 maintains a mapping table as shown in Table 4 below (30-2 to 03-2). ).

               Mapping Information   Internal address (private IP)   External Address (Certified IP)   IP: # 1 Port: $ 1   IP: # 3 Port: $ 3

               Mapping Information   Internal address (private IP)   External Address (Certified IP)   IP: # 2 Port: $ 2   IP: # 4 Port: $ 4

After the connection with the TCP relay server, each terminal transmits the private IP address (private IP # 1- $ 1) and / or user ID (ID) of the private IP terminal 110-1 to duplicate the private IP. The system can be reconfigured with a unique ID system. Accordingly, the TCP relay server 230 decomposes the packets received from the respective private IP terminals 110-1 and 110-2 to generate a relay table for the private IP address and the public IP address of the corresponding terminal, and manage them as shown in Table 5 below. (304)

                      Relay table User ID Private IP Address Public IP Address A IP # 1- $ 1 IP # 3- $ 3 B IP # 2- $ 2 IP # 4- $ 4 C --- ----

After the registration process is completed, when the first private IP terminal 110-1 needs TCP communication with the second private IP terminal 110-2, the first private IP terminal 110-1 provides a starting address. It uses its own private IP address and port number (private IP # 1- $ 1), and requests a TCP connection with the destination address as the relay server 230's address and port number (authorized IP # 5- $ 5).

Accordingly, the first router 210-1 uses the mapping table to select a public IP address (IP # 3-$ 3) corresponding to private IP # 1-$ 1 from the TCP packet of the first private IP terminal 110-1. After converting the private IP address of the source to the public IP address by assigning the transmission request packet for requesting the public information of the opponent to the destination TCP relay server 230 (306). When a TCP channel is established with the server in this way, the TCP connection information of the other party is requested through the TCP channel. At this time, the payload should include information (user ID) that can indicate the uniqueness of the counterpart for TCP communication.

The TCP relay server 230 extracts the requested private IP address (IP # 2- $ 2) or the user ID (B) from the packet received from the first router 210-1, and then searches the relay table for the counterpart. It finds the public IP address (IP # 4- $ 4) and transmits it back to the first router 210-1 through the TCP channel (307,308). The first router 210-1 transmits the packet including the other party's public IP address (IP # 4- $ 4) received from the TCP relay server 230 to the corresponding first private IP terminal 110-1 (309). .

After acquiring a public IP address for the other party having a private IP address through the same procedure, the first private IP terminal 110-1 requests a TCP connection in which the destination address is a public IP address and the source address is its own private IP address. The packet is generated and transmitted to the other party through the first router 210-1 (310).

The first router 210-1 obtains a public IP address (IP # 3- $ 3) corresponding to private IP # 1- $ 1 in the TCP data packet of the first private IP terminal 110-1 according to the same procedure as described above. After allocating the private IP address to the public IP address, the TCP data packet is transmitted to the public IP address (IP # 4- $ 4) of the destination counterpart (311).

When the second router 210-2 receives the TCP data packet, the second router 210-2 searches for a private IP address (IP # 2- $ 2) corresponding to the public IP address (IP # 4- $ 4) in its mapping table. In step 312, the received TCP data packet is forwarded.

The second private IP terminal 110-2 receives the data by decomposing the received TCP data packet and acquires the public IP address (IP # 1- $ 1) of the counterpart from the source address field of the received packet and responds. If present, the second router 210-2 generates a TCP connection response packet using the obtained public IP address (IP # 1- $ 1) as the destination address and its own private IP address (IP # 2- $ 2) as the source address. Transmit to the other side through the (313).

The second router 210-2 uses the mapping table to convert the private IP address (IP # 2- $ 2) of the source from the TCP data packet received from the second private IP terminal 110-2 using the public IP address (IP #). 4- $ 4) and transmits the TCP data packet to the other party having the destination address (IP # 3- $ 3) (314).

Accordingly, when the first router 210-1 receives the TCP data packet, the first router 210-1 finds the private IP address (IP # 1- $ 1) corresponding to the public IP address (IP # 3- $ 3) in its mapping table. Forward the received TCP data packet to the address (315).

Through this procedure, a TCP connection is established between the first private IP terminal 110-1 and the second private IP terminal 110-2, and after the channel is established, the terminals can transmit data as a TCP connection between public IP terminals. In this way, the first private IP terminal 110-1 and the second private IP terminal 110-2 can communicate in a TCP manner.

4 is a flowchart illustrating a UDP communication process between a private IP terminal and a public IP terminal in the communication environment shown in FIG. 2.

Referring to FIG. 4, private IP terminals need to register their private IP addresses (or user IDs) and public IP addresses corresponding to their private IP addresses in the relay table of the TCP relay server 230 periodically. To this end, the procedure for TCP registration of the first private IP terminal 110-1 to the relay server 230 through the first router 210-1 is the same as described above (301-1 to 304).

In order to know the public IP address of the counterpart using the private IP address, the public IP terminal 220 first connects to the TCP relay server 230 and requests TCP channel information (401). The payload of the channel request packet contains the private IP address (or user ID) of the other party.

Accordingly, the TCP relay server 230 extracts the other party's private IP address (or user ID) from the received packet, searches the relay table, and finds and transmits the public IP address for the other party (402, 403).

The public IP terminal 220, which has obtained the public IP for the other party, generates a TCP connection request packet having a starting address as its own public IP address and a destination address as the other public IP address, thereby creating the other party's first router 210-1. 404.

When the first router 210-1 receives the TCP data packet, the first router 210-1 finds the private IP address corresponding to the public IP address in its mapping table, and delivers the received TCP data packet to the private IP address (405).

If necessary, the first private IP terminal 110-1 transmits a TCP data packet to the public IP address of the public IP terminal 220, in response to the connection request of the other party, to the public IP address of the public IP terminal 220 (406 and 407).

In this way, a TCP connection is established between the first private IP terminal 110-1 and the public IP terminal 220, and then data can be transmitted like a conventional TCP channel (408, 409).

Second Embodiment

5 is an overall configuration diagram illustrating a communication environment for establishing a TCP channel using a service server according to the present invention.

Referring to FIG. 5, a plurality of private IP terminals 110-1 using a private IP address are connected to the first private network 102 to communicate using a private IP address in an internal network 102. The router 210-1 of the private network 102 can connect with other public IP servers and terminals through the Internet 202 using a public IP address. In addition, a plurality of private IP terminals 110-2 using a private IP address are connected to the second private network 104, which is another private network, and communicates using the private IP address in the internal network 104. The router 210-2 of 104 may be connected to other public IP servers and terminals through the Internet 202 using a public IP address. In addition, a plurality of public IP terminals 220 or service servers may be connected to the Internet 202, and a TCP relay server 230 for allowing TCP communication using a private IP address according to the present invention, and to each terminal. A service server 510 that provides any service is also connected to the Internet 202.

6 is a flowchart illustrating a process of establishing a TCP channel using a service server according to the present invention.

Referring to FIG. 6, it is assumed that a communication channel is already established between the first private IP terminal 110-1 and the second private IP terminal 110-2 by the service server 510 (601-1). , 601-2). To this end, terminals repeatedly request TCP registration to the router (301-1,301-2), and the router requests TCP registration from the TCP relay server 230 using a mapping table (302-1,302-2,303-1,303). -2). Accordingly, the TCP relay server registers and manages the TCP relay table (304).

In this state, when switching to the TCP channel and receiving another service, the first private IP terminal 110-1 accesses the TCP relay server 230 through the first router 210-1 to establish a TCP connection. Request 602. That is, since the public IP address corresponding to the private IP address is managed by the mapping table of the first router 210-1 and maintained in the relay table of the relay server 230, the public IP address corresponding to the private IP address is authorized to the TCP relay server 230. Request an IP address. To this end, the first private IP terminal 110-1 has a source address of its own private IP address and a port number (private IP # 1- $ 1), and a destination address of the relay server 230. TCP connection request packet # 3- $ 5) is formed and transmitted to the relay server 230 through the first router 210-1.

The TCP relay server 230 accepts a TCP connection to the connection request of the first private IP terminal 110-1 and establishes a channel (603).

When the channel is established, the first private IP terminal 110-1 transmits a packet requesting the TCP relay server for public information of the second private IP (604). The TCP relay server 230 searches for the requested second private IP terminal 110-2 by using the registration table registered through the registration processes 301 to 304 (605). The TCP relay server 230 returns the retrieved information of the second private IP terminal 110-2 to the first private IP terminal 110-1 (606).

The first private IP terminal 110-1 having obtained the requested information of the second private IP terminal 110-2 requests a connection to the second private IP terminal 110-2 using a service channel (607). . When the second private IP terminal 110-2 receiving the connection request is accepted, the second private IP terminal 110-2 assigns a receiving port to a port registered in the TCP relay server 230, listens for a socket, and accepts the TCP connection to the counterpart 110-1. Send a packet (608, 609).

The first private IP terminal 110-1 receiving the connection acceptance packet from the other party attempts a TCP connection using the other party's authorized information received from the TCP relay server 230 (610). Upon receiving the connection request, the second private IP terminal 110-2 establishes a TCP channel with the first private IP terminal 110-1 by connecting to the request counterpart through the port on which it is listening (611). If a TCP channel is established, then all data can be used the same as the public IP TCP connection. Accordingly, both private IP terminals 110-1 and 110-2 may switch to a TCP channel to exchange TCP data packets (612).

Since the detailed transmission process of the TCP data packet is the same as the TCP data packet transmission procedure of the first embodiment described above, further description thereof will be omitted.

7 is a diagram illustrating an example in which TCP channel information is obtained and then used as it is in another program according to the present invention.

As described above, in the method of establishing a TCP channel, the user may periodically report to the relay server 230 to support the connection by maintaining the TCP channel information of the user in the TCP relay server 230.

In the above method, each of users A, B, and C periodically establishes a TCP connection to the TCP relay server 230 to report its status and update the router information. By doing so, all users requesting a TCP connection always register their connection information in the relay server 230 which is an external public IP system. If the registration is successful, when the user A requests the user B to connect, the relay server 230 requests the counterpart's TCP information, and transmits a connection request message to the user using the service channel. User B accepts the request and listens on the port based on the TCP information already registered. User A attempts to connect to user B using the information received from relay server 230. This establishes a TCP channel between user A and user B. Once a TCP channel has been established, it can be used for data transmission just like a traditional TCP channel.

Referring to FIG. 7, the first private IP terminal 110-1 of the first private network 102 is connected to the Internet 202 through the first router 210-1, and the second private network 104 is connected to the Internet 202. The second private IP terminal 110-2 is connected to the Internet 202 through the second router 210-2, and the Internet 202 has a TCP relay server 230, a service server 510, and a public IP terminal. 220 is connected. In the first private IP terminal 110-1, a TCP application module (for example, a file transfer program) 710-1 for using TCP information (relative IP address, IP # 4- $ 4) obtained according to the present invention. Is connected, and the second private IP terminal 110-2 has a TCP application module (for example, a file transfer program) for using the TCP channel information (relative IP address, IP # 3- $ 3) obtained according to the present invention. 710-2 is connected.

In the present invention, by transmitting the TCP channel information obtained by the private IP terminals 110-1 and 110-2 to the other application modules 710-1 and 710-2, the corresponding application module utilizes the acquired TCP channel information to generate a TCP packet. You can communicate. The method of acquiring TCP channel information is specified in FIGS. 6 and 7. In other application modules 710-1 and 710-2, as shown in FIG. 7, if the ports registered by the terminals 110-1 and 110-2 are not overlapped with each other, the applications can be alternately used by using connection channels. TCP communication is possible between modules.

8 is an overall configuration diagram in which a private IP network and a public IP network are integrated by a plurality of private networks and a plurality of TCP relay servers connected to the Internet according to the present invention.

8, many private networks 102-1 to 102-5 are connected to the Internet 202 through routers 210-1 to 210-5, and a plurality of private IP terminals are connected to each private network. have. All private IP terminals connected to the Internet 202 are guaranteed uniqueness by combining the public IP information of the router with the private IP. In the process of registering public information, all private IP terminals periodically transmit their own public access information (IP address, port) together with their own ID information (eg, information guaranteeing uniqueness; for example, MAC and user service ID). -1,230-2). Through this process, the private IP terminal may register its information with the relay servers 230-1 and 230-2. This information is when the user registered in the relay server (230-1, 230-2) requests the user's TCP connection information using the ID, the relay server (230-1, 230-2) searches the mapping table to the IP address of the request target And port number information.

Using this system, all private IP terminals connected to the Internet can be used as public IP terminals by converting private IP addresses to public IP addresses such as DNS (Domain Name Service). The private IP address terminal only needs to register its TCP connection information with the relay servers 230-1 and 230-2. At this time, if unique data is mapped and stored as duplicated private IP information, uniqueness is guaranteed as a whole, and any user can be interconnected.

As described above, in the related art, a system having a private IP cannot directly access an existing Internet, and thus a server configuration using TCP and communication between private IP terminals of different networks are not possible. It can communicate using TCP like public IP system of. Moreover, as the services of the Internet are diversified, the desired transmission characteristics are varied for each service. The present invention enables a system having a private IP to use TCP in all situations, thereby enabling more efficient communication in the field where optimal service was not possible. Let's do it.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. I can understand that you can.

1 is a schematic diagram illustrating a concept of TCP communication using a private IP according to the present invention;

2 is an overall configuration diagram showing a TCP communication environment between private IP networks according to the present invention;

3 is a flowchart illustrating a TCP packet transmission process between two private IP terminals in different networks in the communication environment shown in FIG.

4 is a flowchart illustrating a TCP communication process between a private IP terminal and a public IP terminal in the communication environment shown in FIG. 2;

5 is an overall configuration diagram illustrating a communication environment for establishing a TCP channel when each communication terminal is connected to a service server according to the present invention;

6 is a flowchart illustrating a process of setting a TCP channel when each communication terminal is connected to a service server according to the present invention.

7 is a view showing an example of using the information as it is in another program after acquiring TCP channel information according to the present invention;

8 is an overall configuration diagram in which a private IP network and a public IP network are integrated by a plurality of private networks and a plurality of TCP relay servers connected to the Internet according to the present invention.

* Explanation of symbols for main parts of the drawings

102,104: Private network 110-1,110-2: Private IP terminal

210-1,210-2: Router 202: Internet

220: public IP terminal 230: TCP relay server

510: service server

Claims (13)

When there is a private IP terminal and a public IP terminal, and the public IP terminal is listening to an arbitrary port, and the private IP terminal is connected to an arbitrary port that the public IP is listening to, A communication terminal device using a series of private IPs that a public IP terminal establishes a connection to a private IP terminal by obtaining an IP and a port from a packet to which a public IP terminal is connected and attempting to connect using the obtained information. TCP packet communication method. A first step of registering private IP terminals with private IP address-approved IP address information in a TCP relay server; A second step of obtaining, by the originating private IP terminal requiring TCP communication, the public IP address of the called private IP terminal from the TCP relay server; A third step of, by the calling private IP terminal obtaining the public IP address of the called private IP terminal, requesting a TCP connection to the public IP address; And And a fourth step of setting up a TCP channel by the destination private IP terminal accepting the TCP connection request and sending an acceptance packet. The method of claim 2, wherein the first step When the private IP terminal requests registration with a private IP address, the router allocates an extra external port to the private IP address, converts it to a public IP address, and transmits a registration request packet to the TCP relay server. A TCP packet communication method for registering TCP information of a communication terminal device using a private IP and using the same, to establish a TCP channel. The method of claim 2, wherein the second step When the private IP terminal sends a TCP channel request packet to the TCP relay server to request the called party's public IP address, the originating router maps the packet's originating private IP address to the public IP address and then sends the TCP channel to the TCP relay server. Send request packets, When the TCP relay server searches the table and sends a channel request response packet containing the called party's public IP address to the calling party's public IP address, the calling router maps to the outgoing private IP address corresponding to the outgoing public IP address of the received packet. TCP packet communication method of a communication terminal using a private IP, characterized in that for transmitting a response packet to the calling private IP terminal. The communication using the private IP according to claim 2 or 3, wherein a mapping table is configured with uniqueness information to replace the duplicated private IP address when the TCP channel is registered. TCP packet communication method of a terminal device. The method of claim 2, wherein the third step When the calling private IP terminal transmits a TCP data packet to the called party's public IP address, the corresponding calling router maps the calling private IP address to the calling party's public IP address and transmits the packet to the called party's router. The destination router transmits the received TCP data packet to the destination private IP terminal by mapping to the destination private IP address corresponding to the destination public IP address. The method of claim 2, wherein the fourth step When the destination private IP terminal transmits a response data packet to the source public IP address, the destination router maps the destination private IP address to the public IP and transmits the response data packet to the source router. And the calling router transmits a response data packet to the called private IP terminal by mapping to the private IP address corresponding to the called party's public IP address. A first step in which private IP terminals register private IP address-approved IP address information in a TCP relay server; A second step of obtaining, by the public IP terminal, the public IP address of the incoming private IP terminal from the TCP relay server; A third step of transmitting, by the public IP terminal acquiring the public IP address of the called private IP terminal, a TCP connection request packet to the called party's public IP address; And And a fourth step in which the receiving private IP terminal receives the TCP connection request packet and transmits a channel connection acceptance packet to set up a TCP channel. In a network in which a TCP relay server manages private IP address-approved IP address information for private IP terminals in a table, and a service channel is formed between a first private IP terminal and a second private terminal belonging to different networks, A first step in which all private IP terminals requiring TCP communication register their own private IP in the TCP relay server; A second step of obtaining, from the TCP relay server, a public IP address of the called private IP terminal by the calling private IP terminal requiring TCP communication; Transmitting a TCP connection request to an incoming private IP terminal through the service channel; A fourth step in which the called private IP terminal receiving the connection request listens to its own port registered in step 1 and transmits a response to the connection request through the service channel; A fifth step of attempting a TCP connection with the called party information obtained in step 2; And And a sixth step of establishing a TCP channel in response to the connection at the called party and transmitting and receiving a data packet using the established channel. A first private IP terminal belonging to the first network and using a first private IP; A first network address translator for mapping the first private IP to a first public IP; A second private IP terminal belonging to the second network and using a second private IP; A second network address translator for mapping the second private IP to a second public IP; And The TCP packet communication system of a communication terminal apparatus using a private IP, characterized in that the TCP relay server for maintaining TCP channel information for TCP communication between the private IP terminals belonging to different networks. 11. The TCP packet communication system of claim 10, wherein a TCP application module for jointly using a TCP channel set in the private IP terminal is further connected. In the Internet where there is a TCP relay server and a large number of private networks and private IP terminals, the relay server manages private IP address-approved IP address information including uniqueness information in a mapping table. A first step in which all the private terminals periodically register their mapping information with the relay server using uniqueness information; A second step of requesting public information (IP address, port) of the private IP terminal using uniqueness information; Address translation that provides public information of a communication terminal device using a private IP, comprising a third step of providing public information by retrieving public information of a private IP terminal corresponding to uniqueness information from a relay server in a mapping table. (Address Resolution) method. The address translation service method of claim 12, wherein a plurality of relay servers are installed on the Internet, and services are provided so that private IP terminals can be used as public IP terminals by providing public IP address information corresponding to private IP addresses.