In order for your device to connect to the outside world (internet) it requires an IP address. In order to obtain an IP address a DHCP server is required. Your device sends out a broadcast message looking for a DHCP server. Which is the start of the process your device and the DHCP server go through for your device to receive an IP Address

The 4-stage process known as D.O.R.A which stands for Discovery, Offer, Request, and Acknowledge, explained below

Discovery – Your device sends out a network broadcast over the network to locate the DHCP Server

Offer – The DHCP server sends an offer message including the IP address, Subnet mask and default Gateway and DNS server information.

Request – Your device receives the offer and sends a message to formally request to use the offered IP address information

Acknowledgement – The DHCP server sends a message back to your device confirming the IP address information.

I’ve set up a small lab with the following topology to show the working of DHCP using a router as a DHCP server

This is the config for the DHCP server on the router

Here is the Packet Capture showing the 4 stage of the DORA process of DHCP.