The Internet Domain Name System (abbreviated DNS) is an Internet directory service much like your telephone book. Using DNS, domain names are translated into their cooresponding IP addresses.
The Domain Name System is also used to control the delivery of email. If your PC cannot access DNS services then you will not be able to access web pages on the internet or send email.
Your ISP, when you signup for an account, provides the DNS services for you.
The Domain Name System consists of three components:
The Domain Name System, then, is a global network of servers whose job it is to translate host names like www.orangetreeweb.com into the cooresponding IP (Internet Protocol) address (206.130.101.53). Without the Domain Name System, we would all have to remember long IP addresses to get to our favorite site. Worse yet, we would have to use these "hard to remember" IP addresses in order to send email to our friends and/or business associates.