DNS stands for Domain Name System. It is the system responsible for mapping a machine name such as www.mandrakesoft.com with the IP address of that machine, in this case: 216.71.116.162 at the time of writing. With DNS, mapping is available in both directions, that is from name to IP and vice versa.

The DNS is composed of a great number of machines all over the Internet responsible for a certain number of names. Each machine is attributed a DNS server to which it can ask to map a particular name with its address. If that server does not have the answer, then it asks to another one and so on. You can also have a local DNS responsible for mapping addresses on your LAN.

We can differentiate two major DNS classes: caching DNS and master DNS servers. The first one only “remembers” a previous request and then can answer it without asking a master DNS server once more. The latter servers are really responsible as a last resort to map an address with a name ‐ or possibly specify that a given name does not map any address.

DHCP is an acronym for Dynamic Host Configuration Protocol. The creation of DHCP has made configuring the network on multiple hosts extremely simple. Instead of having to configure each host separately, you can assign all of the commonly used parameters by the hosts using a DHCP server.

Each time the host boots up, it will broadcast a packet to the network. This packet is a call to any DHCP servers located on the same segment to configure the host.

DHCP is extremely useful in assigning items such as the IP address, netmask, and gateway of each host.