What is DNS and How DNS works? | Practonet

What is DNS?

DNS stands for “Domain Name System”.
The DNS is a naming system for computers, servers and other network devices over the Internet. It is used for resolving hostnames to IP addresses or vice versa. For e.g. hostname www.thelanbook.com has IPv4 address 67.227.49.222 and has IPv6 address 2607:f0d0:1002:11::7. In other words DNS is used for associating a domain name (such as thelanbook.com) to an IP address (such as 67.227.49.222). It just work like the “phone book” for the Internet by translating easy remember computer or server names into IP addresses.

Internet domain names are easier to remember than IP addresses such as 67.227.49.222 (IPv4) or 2607:f0d0:1002:11::7 (IPv6). Using DNS one can remember URLs such as google.com and e-mail addresses without having to know how the machine will actually locate them.

The DNS is suite of protocols that comprise TCP/IP. All major operating systems, network devices, mobile phones, and PDAs supports DNS. DNS is always implemented using two software components:
-The DNS server.
-The DNS client.



How DNS works?

1. You type a domain name such as google.com into your browser using client computer operating system such as Windows or Apple OS (“client”).

2. The client needs to find the IP address where google.com search engine is located on the earth (typically all websites are hosted in the Internet data center).

3. Your browser will send this query to the operating system.

4. Each operating system is configured to query certain dns servers. Typically your ISP or network administrator configures such dns servers called Resolving Name Server.

5. The resolving name server does not aware of the location of the google.com, but it does know where the root servers are located.

6. Next, the resolving name server find the location of the top-level domain name server to send query for google.com. Each domain on the Internet has authoritative name server.

7. Finally, the authoritative name server will give you exact IP address of google.com. This information will come back to to the resolving name server, which caches the information and send backs an answer (answer to your query what is IP address of google.com) to the browser to the correct place. The end result you will see google search engine home page.