DNS is part of the glue that holds the internet together. It comprises IPV4 and IPV6 internet protocol (IP) addresses, which are numbers which translate the domain names you type into your computer browser so that your computer knows exactly where to go in order to fulfil your request. In fact, some types of DNS are actually referred to as "glue" records.
DNS is a set of millions of distributed databases, built in a hierarchy up to a top-level which are called the root servers. When you type in www.google.com, DNS looks this up in the databases and then returns one or more IP addresses for your computer to go and talk to and make a request for www.google.com.
A WHOIS record is the record of your domain name. This domain name record will contain one or more name servers, which are the databases that hold the DNS information for your domain name. Commonly this will contain a number of default records, which can include:
An "A" record is an IPv4 hostname record, also known as the forward lookup.
An "AAAA" record is an IPv6 hostname record, also known as the forward lookup.
An "MX" record is for a mail server, also known as mail exchanger record.A "CNAME" record stands for a canonical name and provides you with an alternate name for a host.
An "NS" record is to query for the nameserver (DNS server) information.
A "PTR" record is another way to do a reverse lookup. It's the same function as the IP address too demonstrated above. You enter an IP address for this kind of query.
An "SOA" record is Source of Authority.
For a fun and informative journey into DNS and to understand more, visit https://howdns.works
