How DNS Resolution Works

What is DNS and why name resolution exists?

DNS (Domain Name System) is often described as the phonebook of internet. It is a hierarchical and decentralized naming system that translates human readable domain names into numerical IP addresses that computers use to locate each other on the internet.

Name resolution exists because:

• Humans are good at remembering names but bad at remembering random numbers.


• It decouples the identity of a service from its location. If a server moves to a new IP address, the DNS record is simply updated.

Understanding the dig Command and the Complete DNS Resolution Flow

Dig is a command line tool used by network administrators to query the DNS. It is used to troubleshoot network issues by verifying that DNS servers are responding correctly and providing the expected IP addresses.

• 
  dig.NS queries the root zone and returns root name server which only point to TLD server not the IP addresses.


• 
  dig com NS queries the .com TLD servers, which tell you which authoritative servers manage domains under .com.


• 
  dig google.com NS finds Google authoritative name server which actually own the DNS records.


• It trigger full DNS resolution via recursive resolver.