Dynamic Host Configuration Protocol (DHCP)
A dynamic host configuration protocol (DHCP) server assigns an IP address automatically to a computer on a network. It can also automatically assign a subnet mask, default gateway, and DNS server at the same time. DHCP is a service that runs on a server or a router.
DHCP saves network administrators from having to configure each computer or device manually.
You can set your computer to obtain an IP address automatically, after which your computer will send a request to the DHCP server. The server will select an IP address from its pool and deliver it to the computer.
Network administrators can establish a "scope" of IP addresses or a range of addresses the DHCP server can choose from. The scope can be adjusted depending on the number of computers and devices in the network.
DHCP servers assign IP addresses on a "lease" basis, which means they have a start and end date. This keeps the server from running out of IP addresses within its scope. If a computer is disconnected from the network, the server will be able to assign its former IP address to another computer or device.
If you want a device to always be given the same IP address, the DHCP server can reserve the IP address for that device based on its MAC address. If the lease expires on the device and the device requests a new IP address, it will get the same one again. This isn't necessary for computers on an network, but it's ideal for printers, servers, and routers.