When you type a website into your web browser, like, for instance, Google.com your computer does not know the IP address. Therefore, it attempts to connect to the internet to make an ARP (address resolution protocol) request. The request is forwarded onto the local DNS (domain name server). The DNS, if it has the IP address, forwards the information back to you. If it does not have the information, it requests the information from one of the thirteen root DNS servers on the internet.