Networking
DNS
Networking |
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| The University of Findlay's College of Education | |
The Internet uses IP addresses for all network communication. Humans are not good at remembering 32-bit numbers. To make it easier for humans to remember Internet addresses, each IP address can be given a name, or more specifically, a domain name. The Internet is configured so that Domain Name Service servers (DNS servers) translate IP numbers into these domain names.
When I tell my computer to connect to
www.network.com
my operating system must first find out the IP address of this remote computer. A message is sent to my DNS server asking for the IP address of the specified server, and it returns
199.117.144.10
My computer then connects to that IP address.
The entire process is a little more complicated if my DNS server does not already know the IP address for the domain name that I have specified. In that case, the following chain of events will happen.
My computer asks the local DNS server for the IP address associated with www.network.com. My DNS server goes to the Root server on the Internet. All new IP requests go to this top level root server (also called "dot"). The root server keeps track of all top level domains (ex: .COM, .NET, .ORG). The root server examines the request, and determines that the information is stored at the top level .COM DNS server. The request is passed to the top level .COM DNS server which passes it on to the top level DNS server at NETWORK.COM. That server will know which IP address is assigned to the WWW domain within the NETWORK.COM network. The corresponding IP address is then sent back to my computer.
The whole process typically takes less than a second.
Trouble Shooting Tip: Memorize the IP address of one computer on the Internet. Make it your school's web server, or some other computer that would be useful for you to reach. If you have Internet connection problems on your computer, try to enter the IP address that you have memorized. If you can connect to that computer, you have a DNS server problem, not a network connectivity problem.