DHCP (Dynamic Host Configuration Protocol)
DHCP is a protocol that lets network administrators automate and centrally manage the assignment of Internet Protocol (IP) addresses to network devices in a network. 

DHCP uses the concept of a "lease" or amount of time that a given IP address will be valid for a computer. The lease time can vary, depending on how long a user is likely to require the network connection at a particular location. 

DHCP also supports static addresses for e.g. computers running web servers, which need a permanent IP address.