If you have a network of computers tied to one gateway and all of them are going to work together more than likely you are going to want a dhcp server (Dynamic Host Control Protocol).

Dhcp servers control the way your computers relate to each other on your network or your intranet. Each peripheral on the network must have its own name and its own ip address (Internet Protocol Address). Each desktop comptuter, each printer, each router, each firewall, each wireless device must have an agreed upon protocol to be able to communicate with each other. The dhcp servers functions like a network brain to keep all of this straight. If you have a small network you really do not need a dhcp server, but the larger your network the more this server is helpful.

If you need a Brain for your network you deserve a dhcp server