Wednesday, 2 July 2014

DNS Its All in a Name

We use them every day, and yet behind the scenes things happen pretty quick to disguise what's really going on. What is it? 

DNS - Domain Name Server.  This is a computer that sits on a network (in this instance the internet) and converts a fancy domain into a slightly harder to remember IP Address.  Confused yet?

Basically, every computer that sits on a network is assigned an IP Address. IPv6 is the newest standard, but for today's purposes we'll look at the IPv4 version, which is a set of 4 numbers separated by a dot.  Each number can go from 0 to 255 so an IP Address might take a format like this - 192.168.0.1

As you can imagine, with each set of numbers ranging from 0 - 254, you can have a lot of numbers. 4,294,967,296 in fact.  You can't have duplicates, so each computer has a unique address on that network.

Now, lets say you want to look at a web page on one of those computers.  I'd like to search for a new watering can, so I might typically go to Ebay to have a look. 

So I go into my internet browser and in the top I type http://23.67.255.200

Ah, browsing Ebay is so much fun. I must Google and find some news to read. Google is http://173.794.41.83


Oh, look out the window, there is my window cleaner. And on the side of his van he has his web site http://94.136.40.103

Wait a minute. That's a bit hard to remember, isn't it? And to make matters worse, tomorrow I might find that Googles IP address has changed as one of their servers might be down for maintenance....

Surely it's easier to remember ebay.co.uk or google.com ?   This is where a DNS Server comes in.  It's job is to keep record of domain names (i.e. google.com) and remember which IP address they point to. When you type google.com in your browser, a Domain Name Server will quickly translate that into the correct and current IP address and your browser will find the web site there.

The importance of a Domain Name Server is apparent, without them running in the background, the internet would be a totally different experience.

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