each computer on the internet needs to be uniquely identified. this is accomplished by assigning each computer a number called an Ip Address. and aip adderss allows for computers to identify and contact each other. an Ip address is a string or numbers, for example, the ip address for google is: 74.125.45.100

if you enter 74.125.45.100 instead of google.com on your browser, it will take you to the google.com website

as humans, its easier to remember, google.com than 74.125.45.100 so thats why DNS come, DNS stands for DOMAIN NAMING SYSTEM

each internet service provider (ISP) or large private network will need one or more DNS server to support the coputers using its network. even networks that do not use the internet will use a DNS server, because its a convinient way to manage addresses in a complex environement. many distrinutions of linux come with a DNS server, the most of which is the most widely use is BIND, BIND stands for BERKELEY INTERNET NAME DEAMON