CN1949784A - IP address requesting method for DHCP client by DHCP repeater - Google Patents

Abstract

The invention discloses a method for a DHCP relay agent of a dynamic host configuration protocol to request an IP address for a DHCP client. Fill in the request message with more than one gateway IP address or more than one network segment address set, and then send it to the DHCP server; B, DHCP server determines from the gateway IP address or network segment address filled in the configuration request message The gateway IP address or network segment address of the subnet to which the DHCP client belongs, assigns the IP address in the address pool corresponding to the determined gateway IP address or network segment address to the DHCP client, and sends the assigned IP address through the DHCP relay to the DHCP client. In the method, the DHCP client only needs one communication interaction with the DHCP server in the process of obtaining the dynamically allocated IP address through the DHCP relay, which saves time and improves efficiency.

Description

Method for DHCP Relay to Request IP Address for DHCP Client

technical field

The invention relates to a technology for a Dynamic Host Configuration Protocol (DHCP) server to assign an IP address to a DHCP client, in particular to a method for a DHCP relay to request an IP address from a DHCP server for a DHCP client.

Background technique

With the expansion of network scale and the improvement of network complexity, the configuration of the network becomes more and more complicated, and the problems that the location of the client changes and the number of clients exceeds the assignable Internet Protocol (IP) addresses often occur. In order to solve the above problems, DHCP technology has emerged. A server using DHCP technology (hereinafter referred to as the DHCP server) can dynamically allocate IP addresses to DHCP clients currently connected to the network, so that the DHCP clients currently connected to the network can pass the assigned The IP address receives the service of the network.

The early DHCP protocol is only applicable to the situation where the DHCP client and the DHCP server are in the same subnet, and cannot cross subnets. That is to say, the DHCP server can only dynamically assign IP addresses in the network segment addresses of the subnet to the DHCP clients belonging to the same subnet. Therefore, in order to dynamically allocate IP addresses to DHCP clients belonging to different subnets in the network, it is necessary to configure DHCP servers in all subnets of the network, which will increase the construction cost of the network.

The introduction of DHCP relay solves this problem: DHCP clients in different subnets of the network can communicate with the DHCP server of the network through the DHCP relay of the subnet, so as to obtain the DHCP server in different subnets of the network. The IP address dynamically assigned by the client. Similarly, the IP address dynamically assigned to the DHCP client in the subnet is still the IP address in the network segment addresses of the subnet. DHCP clients in different subnets of the network can obtain dynamically allocated IP addresses from the same DHCP server through DHCP relay, which not only saves costs, but also facilitates centralized management of the DHCP server.

Generally speaking, the DHCP relay can be a computer or a router, as long as the service program of the DHCP relay agent is loaded in the DHCP relay and started. DHCP relay can be configured with multiple gateway IP addresses, one of which is the master gateway IP address, and the others are slave gateway IP addresses. These gateway IP addresses are the IP addresses of gateways in different subnets, and are used to identify the different Network segment address. In this way, a DHCP relay can manage multiple sub-networks, thereby satisfying the needs of fewer DHCP relay interfaces, distributed addresses of managed network segments, and dynamic address allocation.

In order to dynamically assign an IP address to the DHCP client, the corresponding relationship between the gateway IP address and the address pool or/and the corresponding relationship between the network segment address and the address pool are set in the DHCP server, wherein the gateway IP address is stored in the address pool. Multiple IP addresses that can be dynamically assigned under the address or/and network segment address. That is to say, the address pool storing multiple IP addresses can be identified by the gateway IP address or/and network segment address.

FIG. 1 is a schematic diagram of the application of the DHCP relay in the network in the prior art, as shown in the figure: the DHCP relay communicates with the DHCP server through the Internet (Internet), and four DHCP clients access the DHCP relay.

Fig. 2 is the flow chart of the method for the DHCP client to request the IP address from the DHCP server for the DHCP relay agent in the prior art, and its specific steps are:

Step 200, the DHCP client accesses the subnet and performs DHCP initialization, and broadcasts a configuration request message to the subnet to which it belongs. The configuration request message carries the information of the DHCP client and is used for requesting dynamic allocation of an IP address.

The process for the DHCP client to access the subnet is as follows: the DHCP client connected to the subnet is started, or the DHCP client is currently connected to the subnet and then restarted.

Step 201, the DHCP relay that manages the subnet to which the DHCP client belongs receives the configuration request message through broadcast, fills the gateway field in the configuration request message with the primary gateway IP address configured on the DHCP relay, and configures the The request message is sent to the DHCP server.

Step 202, after the DHCP server receives the configuration request message, determines whether it can be assigned to the DHCP client from the address pool corresponding to the main gateway IP address according to the information of the DHCP client carried in the configuration request message and the main gateway IP address. IP address, if yes, then go to step 203; otherwise, go to step 204.

Since the information of the DHCP client is carried in the configuration request message, the information may include routing information and Media Access Control (MAC) address, etc., so the DHCP server can judge whether the DHCP client belongs to the network with the master gateway IP address based on the information carried. address subnet, so as to determine whether the IP address can be allocated to the DHCP client from the address pool corresponding to the main gateway IP address.

Step 203, the DHCP server obtains an IP address from the address pool corresponding to the main gateway IP address, and returns the obtained IP address to the DHCP client through the DHCP relay, and the DHCP client receives the service of the network through the assigned IP address, and ends .

Step 204, within the set time frame, if the DHCP server does not return the assigned IP address, then request the assignment of the IP address again according to steps 201 to 204 until multiple requests for the assignment of the IP address (generally three times) still do not return the assigned IP address IP address, go to step 205.

In step 205, the DHCP relay agent fills a configured secondary gateway IP address into the gateway field in the configuration request message, and then sends the configuration request message to the DHCP server.

Step 206, after the DHCP server receives the configuration request message, determine whether it can be assigned to the DHCP client in the address pool corresponding to the gateway IP address according to the information of the DHCP client carried in the configuration request message and the slave gateway IP address. IP address, if yes, then go to step 207; otherwise, go to step 208.

Step 207, the DHCP server obtains an IP address from the address pool corresponding to the gateway IP address, returns the obtained IP address to the DHCP client through the DHCP relay, and the DHCP client receives the service of the network through the assigned IP address, and ends .

Step 208, within the set time range, if the DHCP server does not return the assigned IP address, then follow steps 205-208 to fill in the configuration request message with other slave gateway IP addresses in turn, and request an IP address from the DHCP server until The DHCP server returns the assigned IP address to the DHCP client through the DHCP relay or until all slave IP addresses have been tried.

As can be seen from the above scheme, in order for the DHCP client to obtain a dynamically allocated IP address from the DHCP server through the DHCP relay, the DHCP relay and the DHCP server need to perform multiple communication interactions, resulting in the DHCP client receiving the IP address from the DHCP server through the DHCP relay. Obtaining a dynamically assigned IP address takes too long and is inefficient.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a kind of DHCP relay to the method that DHCP client requests IP address to DHCP server, this method is in the process that DHCP client obtains the IP address of dynamic distribution by DHCP relay, only A communication interaction between the DHCP relay agent and the DHCP server is required, which can save time and improve efficiency.

According to above-mentioned purpose, technical scheme of the present invention is achieved like this:

A kind of method that DHCP relay agent of dynamic host configuration protocol requests IP address for DHCP client, the correspondence relation of IP address of Gateway Internet Protocol or/and network segment address and the address pool storing more than one IP address is set in DHCP server, in DHCP The relay sets more than one gateway IP address or more than one network segment address, and the method also includes:

A, the DHCP relay receives the configuration request message sent by the DHCP client through broadcasting, fills in the configuration request message with more than one gateway IP address or more than one network segment address, and then sends it to the DHCP server;

B. The DHCP server determines the gateway IP address or network segment address of the subnet to which the DHCP client belongs from the gateway IP address or network segment address filled in the configuration request message, and assigns the determined gateway IP address or network segment address to the DHCP client. The IP address in the address pool corresponding to the segment address, and the assigned IP address is sent to the DHCP client through the DHCP relay agent.

The setting of more than one gateway IP address in the DHCP relay includes one master gateway IP address and more than one slave gateway IP address.

Described configuration request message also carries the information of DHCP client, and the process of determining the gateway IP address or network segment address of this DHCP client subnetwork described in step B is:

According to the DHCP client information carried in the configuration request message, the DHCP server determines the gateway IP address or network address of the subnet to which the DHCP client belongs from the gateway IP address or network segment address filled in the configuration request message according to the set rules. segment address.

The set one or more gateway IP addresses or one or more network segment addresses filled in step A are all the set gateway IP addresses or all network segment addresses.

The assigned IP address in step B is sent in the configuration message.

When more than one gateway IP address is filled in the configuration request message, before the assigned IP address is sent to the DHCP client through the DHCP relay described in step B, the method also includes:

The DHCP server sends the determined IP address of the gateway to the DHCP client through the DHCP relay agent.

The determined IP address of the gateway is sent in the configuration message.

When more than one network segment address is filled in the configuration request message, before the IP address assigned in step B is sent to the DHCP client through the DHCP relay, the method also includes:

The DHCP server obtains the gateway IP address of the corresponding address pool, and sends the gateway IP address of the corresponding address pool to the DHCP client through the DHCP relay agent.

The gateway IP address of the corresponding address pool is sent in the configuration message.

More than one gateway IP address set as described in step A is filled into the sub-options set in the relay agent information Relay Agent Information option of the configuration request message;

Or more than one network segment addresses set as described in step A are filled into the subnets set in the configuration request message to select the Subnet Selection option.

As can be seen from the above scheme, the present invention uses a plurality of gateway IP addresses or a plurality of network segment addresses configured by the DHCP relay to be filled in the DHCP client during the process in which the DHCP client obtains a dynamically allocated IP address through the DHCP relay. In the configuration request message of the client, send it to the DHCP server, and then the DHCP server determines which gateway IP address or address pool corresponding to the network segment address to assign to the DHCP client according to the information of the DHCP client carried in the received configuration request message The assigned IP address is carried in the configuration message and sent to the DHCP client through the DHCP relay agent. Therefore, in the present invention, in the process of obtaining the dynamically allocated IP address by the DHCP client through the DHCP relay, the DHCP relay and the DHCP server only perform one communication interaction, which saves time and improves efficiency.

Description of drawings

FIG. 1 is a schematic diagram of a typical application of a DHCP relay in a network in the prior art.

FIG. 2 is a flow chart of a method in which a DHCP relay agent requests an IP address from a DHCP server for a DHCP client in the prior art.

FIG. 3 is a flow chart of Embodiment 1 of a method in which a DHCP relay agent requests an IP address from a DHCP server for a DHCP client according to the present invention.

FIG. 4 is a flow chart of Embodiment 2 of a method in which a DHCP relay agent requests an IP address from a DHCP server for a DHCP client according to the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail by giving specific embodiments and referring to the accompanying drawings.

In the present invention, in order for the DHCP client to obtain the dynamically assigned IP address through the DHCP relay, the DHCP relay and the DHCP server only perform one communication interaction, and the DHCP client is filled with more than one gateway IP address configured by the DHCP relay. In the configuration request message of the client, send it to the DHCP server. After receiving the configuration request message, the DHCP server determines which gateway IP address the gateway IP address of the subnet to which the DHCP client belongs to is the gateway IP address filled in the configuration request message according to the information of the DHCP client carried in the configuration request message. The DHCP client is allocated an IP address in the address pool corresponding to the determined gateway IP address.

Similarly, in order to dynamically assign IP addresses to DHCP clients, the corresponding relationship between the gateway IP address and the address pool or/and the corresponding relationship between the network segment address and the address pool are set in the DHCP server according to the prior art, wherein the address Multiple IP addresses that can be dynamically allocated under the gateway IP address or/and network segment address are stored in the pool. That is to say, the address pool storing multiple IP addresses can be identified by the gateway IP address or/and network segment address.

Fig. 3 is the flow chart of the method embodiment one of the method embodiment one that DHCP relay agent of the present invention requests IP address to DHCP server for DHCP client, and its specific steps are:

Step 300 , the DHCP client accesses the subnet and performs DHCP initialization, and broadcasts a configuration request message to the subnet to which it belongs. The configuration request message carries information of the DHCP client and is used for requesting dynamic allocation of an IP address.

Step 301, the DHCP relay that manages the subnetwork to which the DHCP client belongs receives the configuration request message by broadcasting, and fills in all gateway IP addresses (comprising master gateway IP addresses and all slave gateway IP addresses) configured on the DHCP relay into After configuring the gateway field in the request packet, send the configuration request packet to the DHCP server.

Step 302, after the DHCP server receives the configuration request message, according to the information of the DHCP client carried by the configuration request message and all gateway IP addresses, it is determined that the gateway IP address of the subnetwork to which the DHCP client belongs is the configuration request message according to the allocation rule. The master gateway IP gateway address or which slave gateway IP address filled in the text allocates an IP address to the DHCP client from the address pool corresponding to the determined gateway IP address.

The allocation rule of the present invention is existing in the prior art, for example, the gateway IP address can be determined according to the MAC address or the asymmetric subscriber line (ADSL) account information in the DHCP client information carried in the configuration request message.

Step 303 , the DHCP server returns a configuration message to the DHCP relay that sent the configuration request message, and the configuration message carries the determined IP address of the gateway and the IP address allocated to the DHCP client.

Step 304 , the DHCP relay forwards the configuration message to the DHCP client that sent the configuration request message, and the DHCP client uses the assigned IP address to receive network services through the gateway, which is the device with the determined gateway IP address.

In step 301, the gateway IP address filled in the gateway field in the configuration request message can also be multiple gateway IP addresses configured by DHCP relay, rather than all configured gateway IP addresses, such as the main gateway IP address and multiple gateway IP addresses. The technology of the present invention can be adopted as long as the gateway IP address of the subnet to which the DHCP client belongs exists in the gateway IP address of the slave gateway IP address or multiple slave gateway IP addresses.

At this time, in step 301, the process of filling the gateway field in the configuration request message with a plurality of gateway IP addresses configured on the DHCP relay agent is: the relay agent information in the configuration request message of the prior art ( Add a sub-option in the Relay Agent Information) option, and fill in the multiple gateway IP addresses configured on the DHCP relay in this sub-option. The format of this sub-option is shown in Table 1: Suboption ID (1 byte) length (1 byte) Gateway IP address ((number of addresses × 4) bytes) IANA assignment required Number of addresses × 4 List of multiple gateway addresses, IPv4 addresses

Table 1

The present invention can also set the network segment addresses of the subnets under its jurisdiction in the DHCP relay, and when the DHCP relay requests an IP address from the DHCP server for the DHCP client, it can also add all the set network segment addresses to the configuration In the request message, it is sent to the DHCP server for processing. Concrete process is as described in Fig. 4, and Fig. 4 is the flow chart of the method embodiment two that DHCP client requests IP address to DHCP server for DHCP relay agent of the present invention, and its concrete steps are:

Step 400 , the DHCP client accesses the subnet and performs DHCP initialization, and broadcasts a configuration request message to the subnet to which it belongs. The configuration request message carries the information of the DHCP client and is used for requesting dynamic allocation of an IP address.

Step 401, the DHCP relay that manages the subnet to which the DHCP client belongs receives the configuration request message through broadcasting, fills the configuration request message with addresses of all network segments configured on the DHCP relay, and sends the configuration request message to the DHCP server.

Step 402, after the DHCP server receives the configuration request message, according to the information of the DHCP client carried by the configuration request message and all network segment addresses, determine that the network segment address that the subnetwork to which the DHCP client belongs has is a configuration request according to the allocation rule Which network segment address is filled in the message, assign an IP address to the DHCP client from the address pool corresponding to the determined network segment address, and obtain the gateway IP address corresponding to the address pool of the determined network segment address.

The allocation rule described in the present invention is existing in the prior art, for example, the network segment address can be determined according to the MAC address or ADSL account information in the DHCP client information carried in the configuration request message.

Step 403 , the DHCP server returns a configuration message to the DHCP relay that sends the configuration request message, and the configuration message carries the obtained gateway IP address and the IP address allocated to the DHCP client.

Step 404 , the DHCP relay forwards the configuration message to the DHCP client that sent the configuration request message, and the DHCP client uses the assigned IP address to receive network services through the gateway, which is the device with the obtained gateway IP address.

In step 401, the network segment addresses filled in the configuration request message may also be multiple network segment addresses configured by the DHCP relay agent, rather than all configured network segment addresses, as long as there are DHCP clients in the filled network segment addresses The network segment address of the subnet to which it belongs can adopt the technology of the present invention.

At this time, in step 401, the process of filling the configuration request message with a plurality of network segment addresses configured on the DHCP relay agent is: revise the existing subnet selection (SubnetSelection) option in the configuration request message, That is, by adding multiple subnets, Table 2 shows the format of the existing Subnet Selection option defined in the DHCP standard: type value (1 byte) Subnet address length (1 byte) 4 bytes 118 4 subnet address

Table 2

Table 3 is the format of the Subnet Selection option that the present invention repairs: type value (1 byte) 1 byte Variable length (number of subnets x 4) 118 Number of subnets × 4 List of multiple subnet addresses, 4 bytes each

table 3

From the scheme described in Fig. 3 and Fig. 4, it can be seen that the present invention adopts a plurality of gateway IP addresses or a plurality of network IP addresses configured by the DHCP relay agent in the process of the DHCP client obtaining a dynamically allocated IP address through the DHCP relay agent. The segment address is filled into the configuration request message of the DHCP client and sent to the DHCP server. The DHCP server determines which gateway IP address or network address to assign to the DHCP client according to the information of the DHCP client carried in the received configuration request message. The IP address in the address pool corresponding to the segment address, carries the assigned IP address in the configuration message and sends it to the DHCP client through the DHCP relay agent. Therefore, in the present invention, during the process of obtaining the dynamically allocated IP address by the DHCP client through the DHCP relay, the DHCP relay and the DHCP server only perform one communication interaction, which saves time and improves efficiency.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention. within the scope of protection.

Claims (10)

1, a kind of dynamic host configuration protocol DHCP relaying is the method for dhcp client request IP address, it is characterized in that, gateway Internet protocol IP address is set or/and the corresponding relation of the address pool of network segment address and an above IP of storage address in Dynamic Host Configuration Protocol server, at DHCP relay more than one gateway ip address or more than one network segment address are set, this method also comprises:

The configuring request message that A, DHCP relay send to dhcp client by broadcast reception, in this configuring request message, fill set more than one gateway ip address or more than one network segment address after, send to Dynamic Host Configuration Protocol server;

Determine the gateway ip address or the network segment address of sub-network under this dhcp client in gateway ip address that B, Dynamic Host Configuration Protocol server are filled or the network segment address from this configuring request message, to dhcp client distribute the IP address in definite gateway ip address or the network segment address corresponding address pond, institute's IP address allocated is sent to dhcp client by DHCP relay.

2, the method for claim 1 is characterized in that, describedly at DHCP relay more than one gateway ip address is set and comprises a primary gateway IP address and more than one from gateway ip address.

3, the method for claim 1 is characterized in that, described configuring request message also carries the information of dhcp client, and step B is described to determine that the gateway ip address of the affiliated sub-network of this dhcp client or the process of network segment address are:

Determine the gateway ip address or the network segment address of sub-network under this dhcp client in gateway ip address that the information of the dhcp client that Dynamic Host Configuration Protocol server carries according to this configuring request message is filled according to the rule of setting or the network segment address from this configuring request message.

4, the method for claim 1 is characterized in that, the set more than one gateway ip address of the described filling of steps A or more than one network segment address are set all gateway ip address or all network segment addresses.

5, the method for claim 1 is characterized in that, the described institute of step B IP address allocated is carried in the configuration messages and sends.

6, the method for claim 1 is characterized in that, when in described configuring request message, filling more than one gateway ip address, step B is described institute's IP address allocated is sent to dhcp client by DHCP relay before, this method also comprises:

Dynamic Host Configuration Protocol server sends to dhcp client with the gateway ip address of determining by DHCP relay.

7, method as claimed in claim 6 is characterized in that, described definite gateway ip address is carried in the configuration messages and sends.

8, the method for claim 1 is characterized in that, when in described configuring request message, filling more than one network segment address, step B is described institute's IP address allocated is sent to dhcp client by DHCP relay before, this method also comprises:

Dynamic Host Configuration Protocol server obtains the gateway ip address in corresponding address pond, and the gateway ip address in corresponding address pond is sent to dhcp client by DHCP relay.

9, method as claimed in claim 8 is characterized in that, the gateway ip address in described corresponding address pond is carried in the configuration messages and sends.

10, the method for claim 1 is characterized in that, the described set more than one gateway ip address of steps A is filled into the sub-option that is provided with in the relay agent information Relay AgentInformation option of configuring request message;

Perhaps the described set more than one network segment address of steps A is filled into the subnet that is provided with in the configuring request message and selects Subnet Selection option.

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