DNS stands for Domain Name System. It is used to point an incoming domain name towards the IP address of the server. This allows you to change web hosting without changing your domain name. Each website has a specific IP address, and the DNS records pair that IP address to the domain.
A nameserver is a server inside a data center with DNS software installed on it, designed to manage the records of all domains hosted by the company. A host installs DNS software on each server as a means to transfer the data from the DNS records. All incoming information arrives at the nameserver before being routed to its intended destination.
A DNS zone consists of the following records:
NS: It specifies DNS servers for your domain.
A: It specifies IP addresses corresponding to your domain and its subdomains.
MX: It specifies where the emails for your domain should be delivered.
CNAME: It specifies redirects from your domain's subdomains to other domains or subdomains.
SPF: Sender Policy Framework is an attempt to control forged e-mail.
A record (Address Record) points a domain or subdomain to an IP address. It allows users to type in an easily recognisable domain and still get pointed to the IP address. An A record will point to an IP. It is different from name server entry. A name server entry will point to some name servers.
CNAME (Canonical Name Record) redirects one domain to another, allowing you to only update one A record each time you make a change. It points to another domain address rather than an IP address.
MX (Mail Exchange Record) record matches the domain name to a list of servers that handle mail for the domain, and tags each server with a priority. The highest priority is 0. The MX mechanism provides the ability to run multiple mail servers for a single domain, and allows administrators to specify an order in which they should be tried.
This record is the same as an A record, but it allows you to point a domain to an IPv6 address instead of an IPv4 one.