What is DNS (Domain Name System)?

DNS is a unique URL that is human readable like “facebook.com” which maps to some IP address 192.123.53.12, a unique address recognized by computers on the web.

When we enter “facebook.com” on the browser, the browser says to the DNS can you please tell me the IP address of this website, because this IP address belongs to a server that holds the HTML/CSS/JavaScript files required to build Facebook website.

Big companies like Facebook have millions of IP addresses because they need to give files to many users to access Facebook websites.

The point to note here is that a company doesn’t have to own a single IP address, instead they own multiple addresses.

What is IPv4 & IPv6?

IP stands for Internet Protocol. IPv4 is in a specific format like 192.123.53.12

Total IPv4 = 4.29 x 10^9

When the internet was created, we didn't know how many unique IP addresses were required, hence only 4.29 x 10^9 unique addresses were created.

Now in the present time, we have a lot of different websites because now everything is on the internet, so a new internet protocol was created "IPv6". Which also has a special format like 2fa3:2b80:ba01:1:1acc:ffca::5 this increased the amount of capacity.

Total IPv6 = 3.4 x 10^38

How does a DNS know which IP address to send back?

DNS maintains both IPv4 & IPv6 and usually, our browsers like Chrome tells DNS which version of the IP address we require in the request it is sending.