Learn the DHCP series (ix) DHCP relay, analysis

This section focuses on the concept, analysis, and implementation of DHCP relaying.

In some cases, we need to automatically configure IP addresses, gateways, and other network information for clients that are not on the same network segment, and the default DHCP does not seem to achieve this directly, so we need to use a small program, the DHCP Relay agent. It is designed to provide a bridge between a DHCP server and a DHCP client that is not on the same network, allowing the DHCP client's request packet to be forwarded to a DHCP server within another network to achieve the purpose of automatically assigning information such as IP addresses.

To better understand the whole process, here is a demonstration to show the process, first look at the network topology. The following figure:

As you can see, we need to prepare 3 hosts, two servers, one DHCP server, another dual network adapter DHCP relay proxy server, and if currently there is a routing device that supports DHCP Relay agent functions (such as routers), this can be completely replaced with routing devices. There is no problem. I'm replacing it with a Windows2003 DHCP relay, which is used by the client to verify the results of the experiment.

The ultimate goal of the experiment is for the client to automatically obtain a 10.0.0.X IP address, and the DHCP server is 192.168.1.1.

Now we do it step-by-step, please pay special attention to the DHCP server gateway settings,

First, install DHCP and configure scopes

This step is not repeated here, as detailed in this series (iv). After the configuration is complete, the following figure: