How does DHCP work?

Let's start by describing how DHCP actually works. We'll begin by looking at how the packets work in DHCP requests and responses – what information is requested by the client, what the server supplies, and how that works. We'll then move on to start a discussion on how DHCP options can help in many implementations.

Basic DHCP operation

DHCP allows system administrators to centrally define device configurations on a server, so that when those devices start up, they can request those configuration parameters. This central configuration almost always includes the basic network parameters of IP address, subnet mask, default gateway, DNS server, and DNS domain name. What this means in most organizations is that in most cases, almost no devices get static IP addresses or other network definitions; all workstation network configurations are set by the DHCP server. As we explore the protocol more deeply, you'll see other uses for DHCP that...