Chapter 24: DNS and DHCP

Overview

Two key services can help every Linux computer manage hostnames and IP addresses. The Domain Name Service (DNS) is typically configured as a database of hostnames or domain names and IP addresses. The Dynamic Host Configuration Protocol (DHCP) enables you to ration IP addresses by leasing them to different computers on your LAN. As with most other Linux services, both DNS and DHCP include a client and a server.

The Linux DNS server is based on Berkeley Internet Name Domain (BIND) software, and can be configured through a series of files in /etc and /var/named . It is also known as a nameserver, using the named daemon. Any Linux computer that is configured to use TCP/IP is by default configured as a DNS client. When you look for a website, your computer acts as a DNS client. It looks to the DNS server for the associated IP address so it knows where to send its message on the Internet.

A DHCP server can lease IP addresses and provide other key information that allows your computer to define itself on your LAN. DHCP servers can be configured with information that enables your computer to access external networks, find other important servers, and more. Red Hat Linux has changed the name of its DHCP client a number of times in recent years , but the functionality is still the same. It gets IP addresses from a DHCP server, and it collects any other information available from that server.