Here's a concise collection of answers about the inner workings of the internet.
What is DNS (Domain Name System)?
Websites have both a "friendly" address, called a Uniform Resource Locator (URL) and an IP address. People use URLs to find websites, but computers use IP addresses to find websites. DNS translates URLs into IP addresses (and vice versa). For example, if you type http://www.microsoft.com into the address bar in your web browser, your computer sends a request to a DNS server. The DNS server translates the URL into an IP address so that your computer can find the Microsoft web server.