KR100241354B1 - Interlocking system between dhcp server and dns server - Google Patents

Abstract

The present invention provides a system for interworking with the Internet standard name server DNS to solve the confusion of IP addresses caused by the protocol DHCP that automatically assigns IP addresses necessary for a computer to function as a host on the Internet. It is about a method.

The present invention, the DHCP server 10 has a DNS control module 100 for generating and processing a communication message for the function of adding, modifying, deleting the host name and IP address for communication with the DNS server 20; In addition, the DNS server 20 has a DHCP processing module 22 which is responsible for database operation on the requested host name and IP address from the DHCP server 10 for automatic IP address assignment and generates a response message. It is possible to configure and manage the change of dynamic IP address by DHCP consistently through interworking between DHCP, which is a protocol that provides convenience of automatic IP address assignment, and DNS, which provides name service of the Internet. By ensuring transparency, users can avoid confusion in destination addressing caused by DHCP's IP address dynamic allocation.

Description

Interworking system between DSC server and DS server and its method

The present invention provides a DHCP server and DNS (Domain Name) for guaranteeing the integrity of a host against dynamic changes in IP addresses in a network using DHCP (Dynamic Host Configuration Protocol) over TCP (Transmission Control Protocol) / IP (Internet Protocol). System) The present invention relates to an interworking system and a method between servers.

In DHCP, administrators can specify IP addresses and parameters of multiple terminals collectively on the server. However, since the IP address can be changed dynamically, there is a communication inconvenience. In this case, in order to facilitate communication, it is necessary to provide a name server to manage the host name and the IP address in a corresponding state. So when communicating with a DHCP client, ask the name server to look up its IP address to specify the host name. To achieve this structure, Microsoft's and Sun's DHCP servers have the ability to change the name server's database. However, Microsoft uses its own name server, called the Windows Internet Naming Service (WINS) and Sun's Network Information Service (NIS). This is because the existing Unix standard name server, DNS, does not have a structure for dynamically changing IP addresses, which makes it incompatible with the existing DNS and has a dependency on a specific product.

The technical problem of the present invention is to solve the problem of interoperability with the name server to solve the dynamic fluctuation of the IP address which is a disadvantage of DHCP and the original name server appearing in the existing interworking method.

In order to solve this problem, it is necessary to integrate with DNS, which is a UNIX standard name server. Thus, coordination between DHCP and a name server is required, which is an improvement in the algorithm of the DHCP server to send a message requesting the DNS to search and update the database, and the message of the DHCP server in DNS, an existing TCP / IP standard name server. Additional extensions are required to handle. In addition, the messages exchanged between them need to be defined.

An object of the present invention is to provide a system and method for interworking with an Internet standard name server (DNS) in order to compensate for the shortcomings of DHCP in a network using DHCP.

The interworking system and the method according to the present invention use DHCP to reduce the manual work related to IP address allocation and configuration required when adding or changing a new host on a network, so that users can access the network more easily. In addition, confusion due to dynamic change of IP address by DHCP can be prevented by interworking with DNS.

1 is a system configuration diagram for interworking between the DHCP server and the DNS server proposed in the present invention,

2 is a configuration diagram of an interaction procedure between DHCP and DNS proposed by the present invention;

3 is a message format of DNS to be used in the present invention,

Figure 4 is a block diagram of the operation of the interlock system proposed in the present invention.

<Description of the code | symbol about the principal part of drawing>

1: Ethernet 10: DHCP Server

11: message transmission module (MTM) 12: host configuration module

13: ARP setting module 14: Error reporting module

15: Timer 16, 24: User Datagram Protocol (UDP)

20 DNS server 21 Name service module

22: DHCP processing module 22a: database update unit

22b: message processing unit 23: database

The system structure for interworking of the DHCP server and the DNS server proposed in the present invention shows the overall structure for the interaction between the improved DHCP server and the DNS server, as shown in Figure 1, which is the DHCP server 10 and DNS server 20 is connected to the inner net (1).

First, the DHCP client portion is the same as the existing implementation model configuration, and the DHCP server 10 is connected to the message transmission module (MTM) 11 having a data transmitter and receiver, and the message transmission module 11 to host The host configuration module 12, the address resolution protocol (ARP) configuration module 13, the error reporting module 14, the timer 15, and the user datagram protocol (UDP) 16 are configured. The same function as the DHCP server 10 of the same function, and in the DHCP server 10 is configured to include a DNS control module 100 added for interworking with the DNS server 20 according to the present invention.

The DNS control module 100 is a processing module for adding, modifying and deleting host names and IP addresses to a name server through communication with the DNS server 20 before the DHCP server 10 assigns an IP address. This module generates and processes a message that can communicate with the DNS server 20. And other modules of the DHCP server 10 will function the same as the existing DHCP implementation model.

DNS server 20 is largely composed of a name service module 21 and the DHCP processing module (22). In this case, the name service module 21 performs a function of the existing DNS, and when the message requesting processing from the DHCP server 10 is transferred to the DHCP processing module (DPM) 20. The added DPM 20 is responsible for the database operation for the requested host name and IP address from the DHCP server 10 and generates a response message, which is processed by the database updater and the message handler, respectively.

Operation for interworking between the DHCP server 10 and the DNS server 20 is as shown in FIG. The existing message exchange procedure between the DHCP client 30 and the DHCP server 10 is the same, and newly defines a message exchange procedure between the DHCP server 10 and the DNS server 20.

The DHCP client 30 transmits a DHCPDISCOVER message requesting whether the IP address can be provided to the DHCP server 10 managing the IP address (S1), and a DHCPOFFER message (S2) received from the DHCP server 10. After selecting one of the DHCP server 20, and transmits a DHCPREQUEST message (S3). Upon receiving this message, the DHCP server 20 requests the DNS server 20 to update the host name requested by the DHCP client 30 and the IP address to be assigned (S4), and corrects the database of the name server. Afterwards, the DNS server 20 transmits an update confirmation message to the DHCP server 10 (S5).

After the message exchange with the DNS server 20, the DHCP server 10 delivers a DHCPACK message to the DHCP client 30 (S6) to terminate the IP address allocation.

In addition, when receiving a DHCPRELEASE message from the client (S11), the DHCP server 10 and the DNS server 20 performs the same message exchange process. That is, the DSCP server 10 receives the DHCPRELEASE message from the DHCP client 30 (S11) and delivers it to the DNS server 20 (S12), and the DNS server 20 deletes and transmits the host name. The DNSACK message is received (S13) and terminated.

In order to communicate between the DHCP server 10 and the DNS server 20, a definition of a message is required. Thus, the message format used between the two servers uses the existing DNS message format as shown in FIG. This allows for compatibility with existing messages by adding parameter values within the message without modifying the DNS message format. Here, the DNS message format is divided into lower 16 bits (0 to 15 bits) and upper 16 bits (16 to 31 bits) in the head part, so that the identifier and flag, the query number and the response RRs number, and the authority RRs The header part consists of a 16-bit field whose number and additional RRs are numbered, followed by query, response, authority, and additional information fields, which contain several numbers of the original data.

In the flag field,-. 1 bit QR: Query (0), Response (1),-. 4-bit opcode (hereinafter referred to as opcode): standard query (0), reverse query (1), server status request (2),-. 1 bit AA: Means a reliable response-. 1 bit TC (truncated): Return only the first 512 bytes when exceeding 512 bytes in UDP,-. 1 bit RD (recursion desired): The server responds to the query itself when configured.-. 1 bit RA (recursion available): If the server supports recursion, set 1 in the response.-. 3-bit (zero): all 0's,-. 4-bit rcode (return code): indicates no error (0) or name error (3).

It is possible to express a new message type to be transferred between both servers through the range extension of opcode (Oh, P, Code), which is 4 bits in the flag field of the DNS message header shown in FIG. The opcode of the existing DNS takes a value of 0,1,2. DNSUPDATE (S4), a message for requesting a database update of DNS, specifies an opcode value of 8. DNSDELETE (S12), which requests the deletion of a host name and IP address in a database, sets a value of 9 for an opcode value. Will be specified. In addition, the DNSACK message (S4) (S13) is a response message for the DNSUPDATE (S4) and DNSDELETE message (S12) is the same as the response message of the DNS and is confirmed by the return code value.

In order to process DNS messages, each server needs a message processing module, and each module can check that the message is from the DHCP server 10 by checking the value of the opcode. In this way, it is easy to compensate for the disadvantages of DNS and the disadvantages of DHCP while accommodating the advantages of the existing DHCP.

As shown in FIG. 4, even if the IP address assigned by the DHCP server 10 changes by giving the DHCP server 10 an access to the DNS server 20, the same client host can be designated and communicated. Done. It has the ability to dynamically change the DNS database by dynamically defining the database in DNS, which is a UNIX standard nameserver, and defining values in specific fields in messages.

When the interworking system between the DHCP server and the DNS proposed in the present invention is used, the change of the mobile host or the dynamic IP address is achieved through the efficient operation of IP address, which is an advantage of DHCP, and the linkage operation of the DNS server, which is a standard name server of TCP / IP. Transparency can be guaranteed to the hosts that are generated, the manual management of DNS management is reduced, DNS has the ability to automatically update the database, and it will be compatible with the existing network operated by DNS. will be.

Claims (6)

DHCP server 10 and DNS server 20 for consistently managing the change of dynamic IP address by DHCP through interworking between DHCP, a protocol that provides convenience of automatic IP address assignment, and DNS, which provides a name service of the Internet. In the interlocking system of), Communication message for functions such as adding, modifying and deleting a host name and an IP address to a name server through communication with the DNS server 20 before the DHCP server 10 assigns an IP address in the DHCP server 10. DNS control module 100 for generating and processing is further included, The DNS server 20 is provided with a database updater 22a and a message processor 22b to handle database operations on the requested host name and IP address from the DHCP server 10 and to generate a response message. The interworking system between the DHCP server and the DNS server, characterized in that the DHCP processing module 22 further comprises. DHCP server 10 and DNS server 20 for consistently managing the change of dynamic IP address by DHCP through interworking between DHCP, a protocol that provides convenience of automatic IP address assignment, and DNS, which provides a name service of the Internet. In the interlocking control method of The DHCP server 10 adds a DNS control module 100 for generating and processing a communicable message for a function of adding, modifying, and deleting a host name and an IP address for communication with the DNS server 20, and The DNS server 20 is configured by adding a DHCP processing module 22 that is responsible for database operation for the requested host name and IP address from the DHCP server 10 and generates a response message, The DHCP client 30 transmits a DHCPDISCOVER message (S1) requesting whether the DHCP server 10 managing the IP address can provide an IP address, The DHCP client 30 selects one DHCP server 20 from the DHCPOFFER message S2 received from the DHCP server 10, and transmits a DHCPREQUEST message S3; Upon receiving this message, the DHCP server 20 requests the DNS server 20 to update the host name requested by the DHCP client 30 and the IP address to be assigned (S4), After modifying the database of the name server DNS server 20 delivers an update confirmation message to the DHCP server 10 (S5), After exchanging the message with the DNS server 20 through the above steps, the DHCP server 10 delivers a DHCPACK message S6 to the DHCP client 30 to terminate the IP address assignment. How to control interworking between DNS servers. The method according to claim 2, wherein when receiving a DHCPRELEASE message from the DHCP client 30 (S11), the DSCP server 10 receives a DHCPRELEASE message from the DHCP client 30 (S11) and the DNS server 20 (S12), and the DNS server 20 receives and terminates the DNSACK message (S13) by deleting and transmitting the host name (S13). According to claim 2, wherein the format of the message for communication between the DHCP server 10 and the DNS server 20, Use the DNS message format, but add the values of the parameters in the message without modifying the DNS message format to make it compatible with existing messages. DNS's message format includes identifiers and flags that are distinguished by the lower 16 bits (0 to 15 bits) and the upper 16 bits (16 to 31 bits) in the head, the query and response RRs numbers, and the authority RRs. And the additional RRs are each 16 bit field heads, The query part, response, authority, and additional information fields are formed in the body part, and these are control methods for interworking between a DHCP server and a DNS server, including several numbers of original data. The flag field of claim 4, wherein the flag field of the head portion comprises: 1 bit QR representing the query (0), the response (1); A 4-bit opcode representing standard query (0), reverse query (1), server status request (2); 1 bit AA for a reliable response; 1 bit of TC (truncated) that causes only the first 512 bytes to be returned when UDP exceeds 512 bytes; 1 bit of RD (recursion desired), meaning that the server responds to the query itself when configured; 1-bit recursion available (RA), set to 1 in response if server supports recursion Three bits (zero) meaning all zeros; A method for interworking control between a DHCP server and a DNS server, comprising a 4-bit rcode (return code) indicating no error (0) and a name error (3). 5. The opcode of claim 4, wherein the opcode of the flag field of the head portion is determined by: DNSUPDATE (S4), a message for requesting a database update of DNS, specifies an opcode value of 8. DNSDELETE (S12), which requests the deletion of a host name and IP address in a database, sets a value of 9 for an opcode value. Specify the DNSACK message (S4) (S13) is a response message for DNSUPDATE (S4) and DNSDELETE message (S12) is the same as the response message of DNS and check by the return code value, the interworking control between DHCP server and DNS server Way.

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