Complete Guide DNS

This guide I am creating after going to a session in my current office. Since my boss was teaching how basically internet works he also gave us deep dive in DNS after that I thought I will do my own research and write my own article here, is it.

Let's begin what is DNS full form is Domain Name Server. So I will be explaining in very basic terms.

So what DNS works like a phonebook or contacts application in your mobile phone will store a name and a number associated with it. The name in DNS case is the website name and the number will be the IP address.

So what happens when you go to your browser and search for some website like www.amazon.com since you want to shop something.

Step1: First the browser will look into the local cache in your system if it does not find the domain name in there it will go to the ISP in the ISP we have something called DNS resolver. For your kind information, ISP is the Internet Service Provider in my case it is airtel or jio. So the ISP has its own DNS resolver and in most the cases, it will store the domain name and the IP address.

Step 2: if the ISP is unable to resolve the Domain name then it will go to Root Domain server so in our case it will not give us the complete location of the server we are looking for www.amazon.com it will find where is the .com server is hosted it will redirect us to Top-level Domain (TLD)

Step 3: TLD will go and search for the authoritative Domain Server and Return us the IP address of the domain name we are looking for The authoritative server has its own recursive server which will also cache the IP address of this domain. Then it will return this IP address and our computer will also cache this IP address.