A method for controlling dynamic distribution of host addresses by multiple dhcp servers

Abstract

The invention discloses a method for controlling multiple DHCP Servers to dynamically allocate host addresses, and relates to the field of data communication. This method adds two messages, DHCPHello and DHCPConsult, for coordinating the relationship between DHCP Servers on the basis of the original DHCP, and makes slight changes to some of the original messages. When there are multiple DHCP servers in the local area network, each server authenticates each other by sending DHCPHello messages, and forms a DHCP Server team after the authentication is passed, thus avoiding malicious intruders pretending to be DHCP servers to carry out DHCP spoofing attacks; After the establishment, each DHCP Server continues to send DHCPConsult messages for the election of the master DHCP server. The election rule is: the one with the most addresses in the address pool is preferred. If the number is the same, the one with the largest loopback address becomes the master server, and the remaining DHCP servers become slave server, only the main server responds to the client's request message. Advantages: In the case of normal dynamic allocation of host addresses, DHCP spoofing attacks are eliminated, and bandwidth waste in links is reduced.

Description

technical field [0001] The invention relates to the field of data communication, in particular to a method for controlling multiple DHCP Servers to dynamically allocate host addresses. Background technique [0002] In a traditional LAN with multiple DHCP servers, the working principle of DHCP is as follows: [0003] 1. When the DHCP client sends DHCPDiscover in broadcast form, all DHCP servers will respond, but the DHCP client only processes the first received DHCPOffer message; [0004] 2. The DHCP client will still broadcast the DHCPRequest message to all DHCP servers, and will add the IP address of the selected DHCP Server and the required IP address in the optional field. The purpose is to tell other DHCP servers that are not selected to clear the corresponding IP address allocation records that have been generated. [0005] Therefore, in the traditional situation where there are multiple DHCP servers, in order to respond to the DHCP client, each DHCP server needs to r...

AI Technical Summary

Problems solved by technology

[0005] Therefore, in the traditional situation where there are multiple DHCP servers, in order to respond to the DHCP client, each DHCP server needs to reply to the request message, but only one of the reply messages will be used, which greatly wastes bandwidth.

At the same time, because there is no verification message between each DHCP server, an intruder with malicious intentions can easily pretend to be a DHCP server to access the LAN, destroying the normal communication between users.

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