Technology
By Frank Cowan

IPS Features

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IPS Features Staff

International Press Service

Demystifying the Domain Name System –

 Why Your Computer Does Not Get Lost

 There are 108,810,358 web sites as of this year. When you type in http://SDX.NET (This is my local great web hosting company) your computer brings up the web site you want.) How does it know where it is?

 It all began in the 1969 with the Defense Advanced Research Projects agency (DARPA). They wanted to connect the research facilities at several universities.

 In the beginning there three only computers hooked up nationwide, with a maximum of up to 255 computers to be connected, as there weren’t that many in the whole world at the time.

 By 1971 there were 213 computers hooked up. Back then you had to memorize the numbers to know which computer you were talking to.

 Eventually the system grew and that resulted in our current numbering system which consists of four numbers separated by dots like “123.123.123.123”. It’s called an IP (Internet Protocol) address.

 That’s a lot of numbers to remember, so they created a text file called “hosts.txt” which had a list of names and the numbers associated with it like “SDX.NET 66.18.41.12”. It’s still available for use today on your computer.

 By the 1980’s there was a growing list of computers and managing your own list using a text file became troublesome and the Domain Name System was created to make life little easier.

 When you register a domain name the registrar sends the domain name and its’ IP address to the internet root name servers. There are 13 root name servers around the globe, and these are called the “Internet Backbone”.

 Through a hierarchical system using the “domain suffix” like “.com” or “.net” the name servers can rapidly look up a domain name and return the IP address associated with it.

 The number it returns is the number associated with your local name server. For SDX.Net its local main name server is 66.18.41.10 also known as ns1.sdx.net. (ns1 being our witty name for name server 1)

 On your computer you can go to Control Panel / Network Connections / Local Area Connection / Properties / ‘TCP/IP’ / Properties.

 There you will find the local name servers you are using.

 If your computer is having difficulty finding any web sites your name servers may not be working; try ours at (Signal Data Inc.) SDX.NET. put in 66.18.41.10 and 66.18.41.11. Ours are always working.

 If you change your own web site hosting you need to change the IP address at your registrar. Because of all the computers everywhere storing your IP address there can be a delay while the 13 global root name servers and all the smaller name servers catch up. In fact to save bandwidth the local name servers only update themselves once every few days.

 Because of this delay you should always leave your web site running at the old web hosting company for a few days while all the local name servers catch up and your web site at your new hosting company (like SDX.NET) becomes visible to your customers.

 So every time you go to a web site three things happen: Lets look for SDX.NET for example

 your computer asks your ISP like Comcast or Bellsouth, for the IP address for SDX.NET

The ISP asks the Internet backbone

The Internet asks SDX’s name server for the IP address and sends it all back to your computer.

 Then and only then your computer sends the IP address and the pages for SDX.NET are returned to your browser.

 There is a little more than that involved but that’s the gist of it.

 That’s the simple explanation. Its all a numeric system, but they built in a way to get the page you want using English – or coming soon – any language

 But alas, the current IP address system of four digits like 123.123.123.123 is almost exhausted. They are bringing out a six digit version which when fully implemented will allow for trillions of IP address’s.

 Think of it, every light bulb, car, every electric outlet could have it’s own IP address. A far cry from when they thought there would never be more than 255 computers in the whole world. Who would need them? Anyway back then computers were a million dollars and took up entire buldings.

 So back to the internet we go – click click click.