So guys, let's start with the introduction to domain name servers.
So domain name server is popularly acronymed as DNS.
DNS is a technology which facilitates the mapping of website name to the IP address as well as it facilitates
the mapping of IP address to website name.
So you can see that DNS technology works both ways.
So in the first case, the DNS technology is used to map the website domain name to an IP address of
a machine which hosts that particular website.
So this is actually the normal functionality of domain name server, and we do this all the time.
So the moment you type a name of a website in your browser and hit the enter key, you are actually
using the DNS.
Right.
So for example, as soon as you type WW dot google.com in your web browser, your machine sends a request
to load the web page of this website from the machine whose IP address is say 8.8.8.8, which is the
IP address of the server which hosts the website Google.com.
So here you can see that you are actually mapping a website name to an IP address.
DNS technology is also used to map the IP address to the website.
Domain name.
That is, it is exactly opposite to the point number A, Right.
So this functionality is called reverse DNS.
For example, you are given an IP address of a server and let us say that the IP address is 8.8.8.8.
Now, given the IP address of the server, you should be able to find that what website is hosted on
that server.
So you can see that this query is exactly opposite to this query.
So mapping of an IP address to the website domain name is done by reverse DNS.
We shall going to discuss both the mechanism of DNS functionality.
In this module.
We will going to discuss normal DNS server.
That is point number eight and we will going to discuss reverse DNS server.
That is point number B in this module.
Without DNS, you would have to be typing the following URL in your browser all the time in order to
access the server's google.com.
In other words, if there was no DNS server then you would have to remember the IP address of all the
websites, which is actually not feasible today.
So you can imagine how important DNS is today.
Can you imagine using your mobile phone without having a functionality of storing the numbers using
contact names?
Right.
The answer is no, not at all.
So DNS is like a phone book for the internet and DNS plays its role whenever you visit some website
or whenever you send an email.
Right.
So you can imagine how important DNS is for the Internet to work.