The DHCP process

Whenever a client connects to a network, it automatically searches for a Dynamic Host Configuration Protocol (DHCP) server. A DHCP server is used to primarily distribute an IP address, subnet mask, default gateway, and Domain Name System (DNS) server configurations to clients. When the client connects, it broadcasts a DHCPDISCOVER message with a destination MAC address of FFFF.FFFF.FFFF and a destination port of 67

The following is the DHCP four (4) way handshake:

Port 67 is open on the DHCP server. A client uses 68 as the source port.

The DHCP server will respond, send a unicast DHCP Offer message back to the client with potentially usable IP configurations. The client will return a DHCPREQUEST back to the DHCP server, letting the server know it's going to accept the IP configurations from the previous message. They will send a DHCP Acknowledgement message to confirm the IP information the client is going to use for network communication.

A simple method to remember the DHCP process is to use an acronym. So D from Discover, O from Offer, R from Request, and A from Acknowledgement. Putting it all together, it spells DORA.