DNS Explained

Simply put Domain Name System (DNS) is the address book of the Internet.

What is DNS?

There are many ways to explain this, lets start with the acronym DNS (Domain Name System). Its purpose is to translate names to IP addresses, for example translating www.google.com to 172.253.63.104. Simply put DNS is the address book of the internet, its purpose is to provide you the answer to a query you ask regarding the true address of a name.

DNS helps us access websites and consume web services seamlessly from anywhere in the world on any device from your bank to Spotify.

Why do we need DNS?

Firstly it helps us humans remember how to get somewhere, think how difficult it would be to remember the Latitude and Longitude of a location rather than its friendly name such as 51.501366,-0.141890 or other wise known as Buckingham Palace.

DNS will translate names to the IP address so that your computer can route a request over the internet, where this can be really helpful is one DNS record can have multiple IP addresses behind its friendly name, this gives the ability to change the IP addresses dynamically and not impact users who consume the service as they will always just use the name.

How does DNS work?

The following steps break down the journey you go on to view a website

1) Enter an address into your web browser such as www.google.com, a query for the IP address of ‘www.google.com.’ is sent to your default name server. The name server is likely provided by your ISP automatically.

2) The request is sent to one of the 13 top level domain (TLD) servers, these know about top level domains such as ‘.com’, this TLD server will resolve the first part of the name ‘google.com’ and provide what DNS name server manages this domain name.

3) A recursive query is now sent to the server which manages ‘google.com’, this sever will now respond to the query of ‘www.google.com’ and knows what the ‘www.’ resolves to. The IP address of this record is sent back in the response.

4) Your web browser can now navigate over the internet to the website and load Google’s website.

Here is a fantastic video created by DNS Made Easy to help visualise the definition and journey you go on when you perform a query.

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