Every device that connects to a network needs a unique IP address. Network administrators assign static IP addresses to routers, servers, printers, and other network devices whose locations (physical and logical) are not likely to change. These are usually devices that provide services to users and devices on the network; therefore, the addresses assigned to them should remain constant. Additionally, static addresses enable administrators to manage these devices remotely. It is easier for network administrators to access a device when they can easily determine its IP address.

However, computers and users in an organization often change locations, physically and logically. It can be difficult and time consuming for administrators to assign new IP addresses every time an employee moves. Additionally, for mobile employees working from remote locations, manually setting the correct network parameters can be challenging. Even for desktop clients, the manual assignment of IP addresses and other addressing information presents an administrative burden, especially as the network grows.

Introducing a Dynamic Host Configuration Protocol (DHCP) server to the local network simplifies IP address assignment to both desktop and mobile devices. Using a centralized DHCP server enables organizations to administer all dynamic IP address assignments from a single server. This practice makes IP address management more effective and ensures consistency across the organization, including branch offices.

DHCP is available for both IPv4 (DHCPv4) and for IPv6 (DHCPv6). This chapter explores the functionality, configuration, and troubleshooting of both DHCPv4 and DHCPv6.