KR20060130811A - Method for translation between ipv4 and ipv6 embedded dns proxy module of distributed data processing and apparatus thereof - Google Patents

Abstract

An IPv4(Internet Protocol version 4)/IPv6 conversion device having a DNS(Domain Name System) proxy server function of a distributed structure therein and a conversion method using the device are provided to enable a DNS response message to which a temporary IPv4 or IPv6 address is assigned to be transmitted to a main processor, so that the DNS proxy function by distributed processing of an IPv4/IPv6 address conversion service can be executed within a single IPv4/IPv6 conversion device. IPv6 and IPv4 ports are connected to IPv6 and IPv4 networks. A main processor(510) performs the following processes. When IPv6 or IPv4 packets are received from hosts of each network through the ports, the packets are decoded in IPv6 and IPv4 interfaces(513,512) in the same IP-level protocol type, and IP header address information of packets received to an IPv4/IPv6 converter(514) through the interfaces(513,512) is converted into an IP type of a network to be transmitted by an NAT(Network Address Translation)-PT(Protocol Translation) method. And, a sub processor(520), when a DNS inquiry message about a particular domain of the main processor(510) is received through an IPC(Inter Process Communication) transceiver(522), searches a DNS table of a memory according to an inquiry type, and sends a DNS response message to the main processor(510) according to an address type of a searched IP.

Description

IPV4 / IPV6 converter with built-in distributed proxy server function and conversion method using the device {Method for translation between IPv4 and IPv6 embedded DNS Proxy module of distributed data processing and apparatus

1 is a block diagram of a NAT-PT service network using a conventional IPv4 / IPv6 conversion device.

2 is a DNS query message signal flow diagram of a conventional IPv4 / IPv6 conversion apparatus.

Figure 3 is a NAT-PT service network using the IPv4 / IPv6 conversion apparatus according to the present invention

      Block diagram.

4 is a block diagram of an IPv4 / IPv6 conversion apparatus according to the present invention.

Figure 5 is a DNS query message signal flow diagram of the IPv4 / IPv6 conversion apparatus according to the present invention.

6 is an IPv4 / IPv6 conversion process using the IPv4 / IPv6 conversion device according to the present invention.

      Shown flowchart.

((Explanation of symbols for main part of drawing))

              500. IP converter 510. Main processor unit

              511.IPC Transceiver 512.IPv4 Matching Unit

              513. IPv6 matching unit 514. IPv4 / IPv6 conversion unit

              514. Control unit 520. Subprocessor unit

              522. DNS Proxy Processing Unit

The present invention relates to an IPv4 / IPv6 conversion apparatus with a built-in proxy server function and a conversion method thereof, and more particularly, domain information is mutually exchanged in a main processor unit by a DNS query message of packet information received through an IPv6 port and an IPv4 port. The domain table management and table search function necessary for the signal processing of the DNS query message in the main processor unit are distributed in the subprocessor unit, so that the proxy server function can be performed in a single protocol conversion unit. The present invention relates to an IPv4 / IPv6 converter having a structure and a conversion method using the device.

Recently, the IPv6 network has been proliferating with the increase of network devices using IPv6. However, since most network devices are mostly used in existing IPv4 networks, interworking between IPv6 networks and IPv4 networks is necessary. For this purpose, IP address translation is required.

In other words, in order for the nodes connected to the IPv6 network and the nodes connected to the IPv4 network to communicate with each other, an address translator for translating the IPv6 address and the IPv4 address is required. -Protocol Translation (NAT-PT) is an address translation and protocol translation technique used in IPv6-IPv4 network.

A host connected to an IPv6 network by NAT-PT can communicate with a host connected to an IPv4 network, and each of the hosts has only an IPv6 and IPv4 stack, and a device that performs NAT-PT is located at the boundary between an IPv6 network and an IPv4 network. Located.

NAT-PT performs two functions. The first is to perform an address translation by placing an IPv4 address pool for dynamically assigning IPv4 addresses to IPv6 nodes each time a session is initiated, located at the boundary router between the two networks. NAT function. It acts as an address mapper and changes the address in the IPv4 and IPv6 packet headers.

The second is Protocol Translation (PT), which adds additional requirements for applications that include IP address or port information in the payload area to perform address translation on the host and dynamically assign and translate addresses. You must use an application level gateway (ALG) to support this.

Typical examples include DNS-ALG and FTP-ALG. DNS-ALG performs AAAA and A format conversion and exchanges address information between DNSv4 and DNSv6.

FIG. 1 is a block diagram of a NAT-PT service network using a conventional IPv4 / IPv6 converter, and FIG. 2 is a flowchart of a DNS query message signal of a conventional IPv4 / IPv6 converter. An IP converter 10 is provided to receive packet information transmitted from the hosts 120 and 220 of each network through the routers 110 and 210 of the IPv6 network 100 and the IPv4 network 200. Interconversion is performed to the protocol required for the host operation of the network (100, 200).

When the DNS query message transmitted with the packet information transmitted from the IPv6 network 100 through the IP converter 10 has an IPv6 address, it is transmitted to the host 220 of the IPv4 network 200 when the IPv4 network is transmitted. The DNS proxy server 20 to which a temporary IPv4 address corresponding to the corresponding domain of 200 is allocated may be further interworked with the routers 110 and 210 of each network 100 and 200.

As illustrated in FIG. 2, the IPv4 / IPv6 protocol converter having such a structure has a longer response time for the DNS query message when interworking between the IP converter 10 and the DNS proxy server 20 for IPv4 / IPv6 address translation. Inevitably, when the number of hosts 120 and 220 connected to each network increases, the amount of data of the DNS proxy server 20 increases rapidly, making it difficult to use a large network connection.

In addition, the IP translator 10 and the DNS proxy server 20 create a separate domain table for translating into an accessible IP address and map the temporary IPv4 and IPv6 addresses transmitted through each network 100 and 200. Since information must be exchanged to perform the process, a dual stack of IPv6 and IPv4 must be mounted between the IP converter 10 and the DNS proxy server 20.

As the DNS query message signal by the dual stack of IPv6 and IPv4 is processed by the DNS proxy server 20, a delay time similar to the response time generated when interworking with the DNS proxy server 20 is generated. By doing so, there is a disadvantage in that the economy is inferior by the addition of another equipment for reducing the delay time as described above.

On the other hand, in order to solve this problem, a separate flash memory or a nonvolatile memory such as Nvram may be installed in the IP converter 10 so that the storage and retrieval of the domain table through the memory may be performed. Since only low-speed non-volatile memory can be used as a production technology, the data processing dash time of the memory is inevitably delayed, which increases the instability of the operating system of the IP converter 10 that requires real-time packet processing. have.

Accordingly, the present invention has been made to solve the above-mentioned disadvantages and problems in the conventional IPv4 / IPv6 conversion apparatus, and the packet received from each host of the IPv4 / IPv6 network through the IPv6 port and the IPv4 port is an IPv4 address or When translating into an IPv6 address, DNS query message for a specific domain name of each network is generated, and DNS table of memory is searched by DNS query message received through IPC block of sub-processor part and it is suitable for protocol environment of each host. By sending a DNS response message with a temporary IPv4 address or IPv6 address to the main processor, the DNS Proxy function is distributed by distributed processing of IPv4 / IPv6 address translation service in a single IPv4 / IPv6 converter without any additional equipment. An object of the present invention is to provide a distributed IPv4 / IPv6 conversion apparatus to be performed.

The above object of the present invention is an IPv6 port and an IPv4 port connected to an IPv6 network and an IPv4 network, and when an IPv6 or IPv4 packet is received from a host of each network through the port, an IPv6 matching unit and an IPv4 in the same IP level protocol format. A main processor unit which is decoded by the matching unit and converted into IP format of the network to be transmitted by the NAT-PT scheme, in which the IP header address information of the packet received by the IPv4 / IPv6 conversion unit through the matching unit, When the DNS query message is received through the IPC transceiver, an IPv4 / IPv6 converter including a sub-processor unit for searching the DNS table in memory according to the query type and transmitting the DNS response message to the main processor unit according to the searched IP address format is provided. Is achieved by

The IPv4 / IPv6 converter receives packets of an IPv6 host and an IPv4 host from each DNS server between an IPv6 network and an IPv4 network interconnected through an IPv6 port and an IPv4 port, and decodes the IPv6 matching unit and the IPv4 matching unit in the same protocol manner. Will be done.

According to the type of packets decoded by the IPv6 matching unit and the IPv4 matching unit, a response packet is directly sent to the host that transmitted the packet, and the packets decoded by the TCP and the UDP are different destinations from the packet transmitted to the IPv4 / IPv6 conversion unit. It is divided into the case of the packet transmitted to allow the application processing of the upper TCP and UDP to be performed.

The address information of each protocol converted by the IPv4 / IPv6 conversion unit must include IPv6 address and IPv4 address information performed in a set of IPv4 addresses. If the target of the conversion is an IPv4 address, a prefix of NAT-PT method is used. ) Is included.

The DNS query message for a specific domain name to which IP address information is converted by the IPv4 / IPv6 conversion unit is transmitted to the subprocessor unit by an IPC transceiver provided in the main processor unit and the subprocessor unit, respectively. The DNS table is searched and the DNS response message is sent to the main processor according to the IP address information.

In this case, the DNS response message is generated by a DNS proxy processing unit embedded in a subprocessor unit, and according to the DNS response message, the main processor unit is a host of each network, including a temporary IPv4 address and a specific prefix according to IPv6 and IPv4 environments. IPv4 address will be assigned and transmitted.

As described above, in the IPv4 / IPv6 conversion apparatus of the present invention, the IP address translation service of the IPv4 / IPv6 conversion unit in which the IP address conversion is performed by the DNS-ALG function is incorporated in a subprocessor unit in the same NAT-PT device. As DNS response is processed by DNS query message processing at DNS interworking unit interworking with memory, DNS Proxy processing time in IPv4 / IPv6 address information translation requested from host of each network is minimized, so system stability is not required without additional equipment. The technical feature is that it can be efficiently improved.

In addition, the present invention the step of receiving the DNS query message of the host via the DNS server of each network via the IPv6 and IPv4 LAN port of the IPv4 / IPv6 conversion apparatus in the main processor unit, and the IPv6 address in accordance with the received DNS query message Requesting a DNS table lookup of the domain by using the IPv4 address information, and if the DNS table of the corresponding domain exists, a DNS response message is received from the host through the main processor according to the IP address information transmitted from the host. Transmitting a DNS message to each DNS server according to the query message type and registering the received IP address information of the corresponding domain in the DNS table if the DNS table of the corresponding domain does not exist; Depending on the IP environment of the host sending the IP address, the temporary IPv4 address and IPv4 / IPv6 conversion method for the prefixes defined by the DNS reply message containing the IPv4 address information assigned a step to be transmitted to each host by way of the main parts of the processor are the object of another designed to provided.

An IPv4 / IPv6 conversion apparatus with a built-in DNS proxy server function of the present invention and a technical effect on the above-described object of the conversion method using the device are shown in the preferred embodiment of the present invention. It will be clearly understood by the following detailed description with reference to the drawings.

3 is a block diagram of a NAT-PT service network using an IPv4 / IPv6 conversion apparatus according to the present invention, FIG. 4 is a block diagram of an IPv4 / IPv6 conversion apparatus according to the present invention, and FIG. The DNS query message signal flow diagram of the IPv4 / IPv6 converter.

As illustrated, the IPv4 / IPv6 conversion apparatus with the present invention, the DNS proxy server function is received from the IPv6 host 120 and the IPv4 host 220 of each network 100 and 200 in the IPv6 environment and the IPv4 environment. IPv6 matching unit 512 and IPv4 matching unit 513, which are decoded in an IPv6 or IPv4 protocol manner, and a destination address of a response packet for an IP address received by the IPv6 matching unit 512 and IPv4 matching unit 513. An IPv4 / IPv6 conversion unit 514 for converting the IP header address information of each network to be transmitted by receiving a packet including the mapped IP address information of the sender, and for setting and operation management according to the conversion environment of the IP information. The main processor unit comprises a control unit 515 for storing and storing the command system and query message information in advance, and an IPC transceiver for transmitting and receiving DNS queries and response messages involved in IP address information conversion of the IPv4 / IPv6 conversion unit 514. 510;

The IPC transceiver 522, which receives a DNS query message for a specific domain having IP address information converted through the main processor unit 510, and a DNS table linked with an internal memory according to the DNS query type. The subprocessor unit 520 is configured as a DNS proxy processing unit 521 which searches a domain and transmits a DNS response message to the sender host via the main processor unit 510 according to the retrieved IP address information.

When the IPv4 matching unit 512 receives the IPv4 packet from the IPv4 host 220 through the IPv4 LAN port, the IPv4 matching unit 512 is decoded by ARP, ICMP, TCP, UDP, etc. according to the IPv4 protocol, and according to the type of the decoded packet according to the ARP, ICMP. In case of a protocol such as the above, a response packet is directly transmitted to the IPv4 host 220 which transmitted the packet.

In addition, the TCP and UDP packets of the decoded IPv4 packet are classified into a case in which the packet is transmitted to the IPv4 host 220 as the sender and a case in which the packet is transmitted to the IPv6 host 120 as another destination, and retransmitted to the IPv4 host 220. In the case of a packet, the application on the upper level of TCP and UDP, which is determined to be serviced for each application packet, is performed.

In this case, if the destination address of the IPv4 packet includes IP header information of the IPv4 network 200, if the packet is forwarded to the same port where the first packet is received, and the destination address information is an IPv4 address mapped to the IPv6 address, IPv4 / IPv6 conversion unit 514 of the packet is transmitted.

On the other hand, when the IPv6 matching unit 513 receives the IPv6 packet of the IPv6 host 120 received through the IPv6 LAN port, the IPv6 matching unit 513 decodes the NDP, ICMPv6, TCP, UDP, and the like according to the type of the decoded packet and the NDP, ICMPv6 and the like. In case of the same protocol, a response packet is directly sent to the IPv6 host 120 transmitting the packet. Like the IPv4 matching unit 512, when the destination address information is an IPv6 address mapped to an IPv4 address, the IPv4 / The IPv6 conversion unit 514 is transmitted.

The conversion request packet received by the IPv6 matching unit 512 and the IPv4 matching unit 513 may have only an IP protocol layer in the packet in the IPv4 / IPv6 conversion unit 514 and a higher application protocol on the TCP / UDP protocol layer. If there is only the IP protocol layer, the main processor unit 510 performs IP address translation of all packets, and packet processing such as FTP or DNS having a higher application protocol is performed by the main processor unit 510. DNS response through the DNS proxy processing unit 521 of the sub-processor unit 520 and the response message transmission and reception are generated and transmitted to the host that sent the query.

First, the IPv4 / IPv6 conversion unit 514 when there is only an IP protocol layer in the conversion packet is transmitted to the packet transmitted from the IPv4 network 200 to the IPv6 network 100 through the control unit 515 of the main processor unit 510. The configured IPv6 prefix is added to the IPv4 address before conversion, and the address information of the IP header is reassembled into an IPv6 packet converted to an IPv6 address.

For example, a packet having IPv1 address information of 201.200.1.1 before conversion has 3FFF :: of the preset NAT-PT IPv6 prefix, and the converted IPv6 address information of the IP header has a format of 3FFF "" 201.200.1.1. Is formed.

In addition, a packet transmitted from the IPv6 network 100 to the IPv6 network 200 is an IPv4 address having lower 64-bit information when the IPv6 address information before translation is received including the IPv6 prefix of the NAT method set by the controller 155. Converted and reassembled into an IPv4 packet, and a representative example thereof shows that in the case of a packet whose IPv6 address information is 3FFF :: 201.200.1.1, the converted IPv4 address information is composed of 201.200.1.1 with the prefix removed.

In addition, when the packet transmitted from the IPv6 network 100 to the IPv4 network 200 is received without including the NAT IPv6 prefix set in the IPv6 address information before the conversion, the controller 155 may use the IPv4 for NAT-PT. In the set of addresses, a new IPv4 address is assigned and reassembled into IPv4 packets. For example, a packet with pre-transition IPv6 address information of 2FFF :: 201.200.1.1 has a NAT-PT IPv6 prefix of 3FFF :: and NAT-PT for NAT-PT. If only 200.200.200.1 remains in the IPv4 address list, the IPv4 address is newly allocated as 200.200.200.1 after searching the list and transmitted to the host 220 of the IPv4 network 200.

On the other hand, if there is a higher application protocol on the TCP / UDP protocol layer, the DNS query message in the DNS packet of the receiving host through the IPv4 / IPv6 conversion unit 514 via the IPC transceiver 511 through the sub-processor unit 520 An internal signal corresponding to a DNS response message for a specific domain is transmitted to the DNS proxy processing unit 521 of the internal domain by searching for the internal DNS table according to the query type of the DNS proxy processing unit 521. Received through the IPC transceiver 511 of the main processor unit 510 generates a DNS response packet to the host that sent the first DNS query to transmit.

In this case, the IPv4 / IPv6 conversion unit 514 manages the NAT-PT address conversion table at the same time, so that the mapped address is converted into the same address until release, and each IPv6 address and the IPv4 address of the conversion target are converted. In the table, the IPv4 address information allocated from the address set of the table must be included, and in case of an IPv4 address, the translation is performed to the address information including the NAT-PT prefix.

Meanwhile, the DNS proxy processing unit 521 of the subprocessor unit 520 may perform a specific domain from the main processor unit 510 through the IPC transceiver unit 522 interworking with the IPC transceiver unit 511 of the main processor unit 510. You will receive a DNS query for the name.

The DNS proxy processing unit 520 searches the corresponding domain name for the received DNS query message through a DNS table stored in a separate memory (not shown) to check whether the corresponding domain is included in the table list, and the DNS If a specific domain corresponding to the query exists in the DNS table, a DNS response message for the domain is transmitted through the IPC transceiver 511 of the main processor 510 according to whether the IP address is in the form of an IPv6 address or an IPv4 address. Done.

However, if there is no information on the corresponding domain when the DNS table is searched, if the DNS query message is AAAA according to the host type A and AAAA received from the main processor 510, the IPv6 network 100 may first be used. DNS query is made to the DNSv6 server, and if there is no corresponding domain information on the DNSv6 server, DNS query is performed to the DNSv4 server.

In addition, if the DNS query message is of type A, in contrast to AAAA type, the DNS query is first performed by the DNSv4 server, and then the DNS query is performed by the DNSv6 server.

When the IP information of the corresponding domain in the IPv4 / IPv6 conversion apparatus 500 is collected through the DNS query message received from the host 120 or 220 of each of the networks 100 and 200, the subprocessor unit The IP address information collected in the DNS table of the memory managed by 520 is registered and updated, and the DNS response message is transmitted to the main processor unit 510.

In this case, when the host transmitting the initial DNS query message through the IPv4 / IPv6 conversion apparatus 500 is an IPv4 environment, if the IP information of the corresponding domain is in IPv6 format, a temporary IPv4 address is internally allocated and transmitted, and vice versa. If the sending host of the DNS query message is in the IPv6 environment, if the IP information of the corresponding domain is in the IPv4 format, the transmission is performed by including a specific prefix before the corresponding domain.

In addition, the subprocessor unit 520 has a built-in nonvolatile memory and interoperates with the DNS proxy processor 521 so that the updated information is periodically backed up in the memory even when the main processor unit 510 is restarted. Even when the power is turned on or off, the latest DNS table information in the memory may be normally maintained.

On the other hand, look at the DNS distributed processing method performed through the IPv4 / IPv6 conversion apparatus of the present invention having the above configuration as follows.

6 is a flowchart illustrating an IPv4 / IPv6 conversion process using an IPv4 / IPv6 conversion device according to the present invention. As illustrated, the IP address information conversion process in the IPv4 / IPv6 environment of the present invention is an IPv4 / IPv6 conversion device (500). Receiving the DNS query message of the host 120, 220 via the DNS server of each network (100, 200) through the IPv6 and IPv4 LAN port of the main processor unit 510 (S101), The DNS query message received by the main processor unit 510 is transmitted to the subprocessor unit 520 through the IPC transceiver 511 (S102), and the IPv6 received by the DNS proxy processor 521 of the subprocessor unit 520. Requesting a DNS table search of a corresponding domain by address and IPv4 address information (S103), and a DNS table stored in a memory built in the subprocessor unit 520 is searched in real time (S104) and corresponds to the DNS table. IP address sent from host if domain exists Receiving a DNS response message to the main processor unit 510 by a DNS query performed through each DNS server according to the information (S107) and the first DNS query message through each port of the main processor unit 510. The DNS response packet including the temporary IPv4 address and the IPv4 address information to which the specific prefix is given by the DNS query performed through each DNS server according to the environment of the host to which the host is sent is sent to each host via the main processor unit 520. It is made a step (S108) to be transmitted.

If the domain does not exist in the DNS table in the search step (S104) of the DNS table, the DNS query is repeatedly performed to each DNS server according to the IP environment of the DNS query host and the query types (A, AAAA) (S105). And registering and updating the received IP address information of the corresponding domain in a DNS table (S106).

In addition, if a normal DNS response message is not received in step S105, in which the query according to the query type is performed to each DNS server, if the initial DNS query is A type, change to AAAA type, and if AAAA type, change to A type again. DNS queries can be made to each DNS server.

As described above, the IPv4 / IPv6 converter incorporating the DNS proxy server function of the present invention has a distributed process of IPv4 / IPv6 address translation service in a single IPv4 / IPv6 converter without additional equipment. In addition to the DNS Proxy function can be performed, the sub-processor unit is implemented in the form of an additional module inside the IP converter, there is an advantage that 100% compatible on the general network when the sub-processor unit is off.

In addition, another effect of the present invention is to minimize the complicated DNS query processing process for users who want to use the Internet through IPv4-based terminal through IPv6 network, thereby reducing the delay time due to fast domain access in Internet service. It enables IPv4 / IPv6 conversion service and operates independently of main processor inside IP conversion device, thus guaranteeing stability in DNS message processing and reducing DNS query signal transmission on the network. There is an advantage to reduce.

Claims (6)

IPv6 matching unit 512 and IPv4 matching unit 513, which are decoded by the IPv6 or IPv4 protocol received from the IPv6 host 120 and the IPv4 host 220 of each network 100 and 200 in the IPv6 environment and the IPv4 environment. ), And the IP of each network to which the IPv6 matching unit 512 and the IPv4 matching unit 513 receive the packet including the destination IP address information to which the destination address of the response packet corresponding to the IP address received is mapped. An IPv4 / IPv6 conversion unit 514 for converting header address information, a control unit 515 for preconfiguring and storing the command system and query message information for setting and operation management according to the conversion environment of the IP information, and the IPv4 / A main processor unit 510 consisting of an IPC transceiver for transmitting and receiving DNS queries and response messages involved in IP address information conversion of the IPv6 translator 514; The IPC transceiver 522, which receives a DNS query message for a specific domain having IP address information converted through the main processor unit 510, and a DNS table linked with an internal memory according to the DNS query type. And a sub-processor unit 520 including a DNS proxy processing unit 521 for searching a domain and transmitting a DNS response message to a sender host via the main processor unit 510 according to the retrieved IP address information. IPv4 / IPv6 converter with built-in distributed proxy server function. 2. The method of claim 1, wherein the IPv4 / IPv6 converter 514 sends a DNS query message in the DNS packet of the receiving host through the IPv4 / IPv6 converter 514 when there is a higher application protocol on the TCP / UDP protocol layer. The internal DNS table is searched according to the query type of the DNS proxy processing unit 521 via the IPC transceiver 511 and transmitted to the DNS proxy processing unit 521 of the subprocessor unit 520 as an internal signal including the conversion request information. By receiving the internal signal corresponding to the DNS response message for a specific domain through the IPC transceiver 511 of the main processor unit 510 is characterized in that to generate and transmit the DNS response packet to the host that sent the first DNS query IPv4 / IPv6 converter with built-in distributed proxy server function. The method of claim 1, wherein the DNS proxy processing unit 520 searches for the domain name of the received DNS query message through a DNS table stored in a separate memory (not shown) and whether the domain is included in the table list. If a specific domain corresponding to the DNS query exists in the DNS table, the IPC transceiver unit 511 of the main processor unit 510 transmits to the corresponding domain according to whether an IP address format is an IPv6 address or an IPv4 address. An IPv4 / IPv6 converter with a distributed DNS proxy server function, which is configured to send a DNS response message to the server. The method of claim 3, wherein the DNS proxy processing unit 520 internally internally if the IP information of the corresponding domain is IPv6 format when the host transmitting the initial DNS query message through the IPv4 / IPv6 conversion apparatus 500 is an IPv4 environment. On the contrary, if the sender host of the DNS query message is in IPv4 format and the IP information of the corresponding domain is in the IPv4 format, the temporary IPv4 address is allocated and transmitted. IPv4 / IPv6 inverter with built-in DS proxy server function. A first step of receiving, by the main processor, a DNS query message of a host via a DNS server of each network 100 or 200 through IPv6 and IPv4 LAN ports of the IPv4 / IPv6 converter 500; The DNS query message received by the main processor unit 510 is transmitted to the subprocessor unit 520 through the IPC transceiver 511 (S102), and is received by the DNS proxy processor 521 of the subprocessor unit 520. Requesting a DNS table search of a specific domain by address information; If the DNS table stored in the memory embedded in the subprocessor unit 520 is searched in real time and the domain exists in the DNS table, the DNS query performed through each DNS server is performed according to the IP address information transmitted from the host. Receiving a DNS response message to the main processor unit 510 by a third step; If the domain does not exist in the DNS table in the search step of the DNS table, the DNS query is repeatedly performed to each DNS server according to the IP environment of the DNS query host and the query types (A, AAAA). A fourth step of registering and updating IP address information in a DNS table;  A temporary IPv4 address and IPv4 address to which a specific prefix is assigned by a DNS query performed through each DNS server according to an environment of a host to which an initial DNS query message is transmitted through each port of the main processor unit 510 are included. A fifth step of transmitting the DNS response packet to each host via the main processor unit 520; IPv4 / IPv6 conversion method of a distributed structure, characterized in that consisting of. The method of claim 5, wherein in the fourth step, if a normal DNS response message is not received, the first DNS query is A type, and if the first DNS query is A type, the AA DNS type is changed to A type so that DNS queries are made to each DNS server again. Distributed IPv4 / IPv6 conversion method characterized in that it further comprises a step.

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