DHCP (Dynamic Host Configuration Protocol) is a protocol which allows
individual devices on an IP network to get their own network
configuration information (IP address, subnetmask, broadcast address,
etc.) from a DHCP server. The overall purpose of DHCP is to make it
easier to administer a large network. The dhcp package includes the
DHCP server and a DHCP relay agent.

You will also need to install the dhcp-client or dhcpcd package, or pump or
dhcpxd, which provides the DHCP client daemon, on client machines. If you
want the DHCP server and/or relay, you will also need to install the
dhcp-server and/or dhcp-relay packages.