DHCP Server is used to distribute IP addresses to the clients in your network. DHCP stands for Dynamic Host Configuration Protocol. It reduces the work burden to a system admin if he/she have to assign IP addresses manually to more than 100+ systems.

Full articles here:
Setup DHCP Server On CentOS 6.5 (Unixmen)
Setup DHCP Server On Ubuntu 14.04 LTS Server (Unixmen)