Installing DHCP and Windows Deployment Services ~ Window Technical Support

DHCP Introduction

When you deploy Dynamic Host Configuration Protocol (DHCP) servers on your network, you can automatically provide client computers and other TCP/IP-based network devices with valid IP addresses. You can also provide the additional configuration parameters these clients and devices need, called DHCP options, that allow them to connect to other network resources, such as DNS servers, WINS servers, and routers.

IP addresses can be configured statically or dynamically. Normally we configure static IP addresses on network devices like routers, switches, firewalls and servers while we dynamically assign IP addresses to computers, laptops, tablets, smartphones etc. The dynamic method uses DHCP (Dynamic Host Configuration Protocol) and in this short article I want to show you how it works. Let’s take a look at the following picture:

On the left side we have a computer without IP address. On the right side there’s a DHCP server configured with static IP address 192.168.1.254. This DHCP server will supply an IP address to our computer, this is how it works:

The computer will send a DHCP discover message. This is a broadcast because it doesn’t have an IP address and it doesn’t know if there is a DHCP server on the network. Of course in our scenario we do have a DHCP server so it will respond to this broadcast as following:

The DHCP server will respond with a DHCP offer message which contains an IP address for the computer (we have to configure the DHCP server to define which IP addresses we want to give). If we want we can also assign a default gateway and DNS server(s) to the computer. The computer will respond to this information:

The computer will send a DHCP Request in response to the DHCP offer message, asking nicely if it’s OK to use the information that it has received. Our DHCP server will respond to this as following: