How dns servers work know the ip address of websit

Question

My question is that suppose my website is "xyz.com" I can access it anywhere in the world, but I'm curious to know how does all the dns servers know the ip address of my website..? I'm little bit confused..

Answer 1

The main process that resolves an IP Address through DNS is referrals. A DNS Server will go through a process to find the Authorative Nameserver for your domain. The Authorative Nameserver is the server that is configured to answer queries for that domain. i.e. the godaddy DNS Servers, if you have purchased, and configured a domain name through them.

If you go to www.example.com from your PC, it will send a query to your configured DNS server, asking for www.example.com

If your configured DNS Server knows that answer already, i.e. it has been asked the same question recently, it will return the answer from cache (as long as it hasn't expired)

If your configured DNS Server doesn't know, then it will find out. In order to find out what server knows the answer, it needs to look up the name server for example.com first.

So the first query the nameserver makes is to the root domain "." (All DNS Servers should have these configured) to find out the nameservers for the .com domain.

When it has an address for the .com domain's nameservers, it will send a query asking for the nameserver for example.com

when it has the address for example.com's nameservers, it will send the original query, for www.example.com, to that server, and return the answer to you (and put a copy in its cache incase anyone else asks)

Note: If you were looking for www.test.example.com then it would have asked example.com for the nameservers for test.example.com instead.