The DHCP protocol enables host systems in a TCP/IP network to be configured automatically for the network as the systems boot. DHCP uses a client-server mechanism. Servers store and manage configuration information for clients and provide that information upon a client's request. The information includes the client's IP address and information about network services that are available to the client.
DHCP evolved from an earlier protocol, BOOTP, which was designed for booting over a TCP/IP network. DHCP uses the same format as BOOTP for messages between the client and server. However, unlike BOOTP messages, DHCP messages can include network configuration data for the client.
A primary benefit of DHCP is its ability to manage IP address assignments through leases. Leases allow IP addresses to be reclaimed when they are not in use. The reclaimed IP addresses can be reassigned to other clients. A site that uses DHCP can use a smaller pool of IP addresses than would be needed if all clients were assigned a permanent IP address.