What Is DNS (Domain Name System)? What is DNS use for?

Introduction to DNS (Domain Name System)

In the world of networking, computers don’t know by names like humans do, they go by numbers. That’s how computers and similar devices talk / identify each other over a network, which is by using numbers such as (Internet Protocol Address) IP addresses.

Domain Name System use for:

Humans on the other hand are comfortable by using names instead of numbers, whether is talking directly to another person or identifying a place, or thing, humans identify with names instead of numbers.  To reduce the communication gap between computers and humans and make the communication of a lot easier, networking engineers developed (Domain Name System) DNS. DNS (Domain Name System) resolves names to numbers, to be more specific it resolves domain names to IP addresses.  When you type in a browser like Internet Explorer, Chrome etc.  DNS will resolve the name to a number because the only thing computers know are numbers.

So, for example, if we would like to open a certain website, we would open our web browser and type in the domain name of that website like www.google.com. Now technically you really don’t have to type in google.com to retrieve the Google web page, we can just type in the IP address instead if we know Google.com IP address.  But since we are not familiar to remembering and dealing with numbers, especially when there are millions of websites on the internet, we can just type in the domain name instead and let DNS convert it to an IP address for us.

When we type in google.com in your web browser the DNS server with search through its database to find a matching IP address for that domain name, and when it finds it will resolve that domain name to the IP address of the Google web site, once that is done then your computer is able to communicate with a Yahoo web server and retrieve the webpage.

As soon root server receives the query for the IP address for google.com, the root server is not going to know what the IP address is, but the root server does know where to send the resolver to help it find the IP address. The root server will direct the resolver to the TLD or top-level domain server for the dot com domain. So, the resolver will now ask the TLD server for the IP address for google.com. The top-level domain server stores the address information for a top-level domain, such as .com, .net, .org and so on. This TLD server manages the dot-com domain which google.com is a part of.  As soon when a TLD server receives the query for the IP address for google.com, the TLD server is not going to know what the IP addresses for google.com. So, the TLD will direct the resolver to the next and final level, which are the authoritative name servers.  So once again the resolver will now ask the authoritative name server for the IP address for google.com.  The authoritative name server or servers are responsible for knowing everything about the domain which includes the IP address. They are the final authority. So, when the authoritative name server receives the query from the resolver, the name server will respond with the IP address for google.com. And finally, the resolver will tell your computer the IP address for yahoo.com and then your computer can now retrieve the Google web page.