IP address was difficult for an individual to remember all the IP addresses to access the websites. So the domain names were created and mapped with IP addresses.

In earlier websites were accessed through their IP addresses.

Internet Corporation for Assigned Name and Numbers, Non - profit organization which regulates an Internet.

There are three types of Name Servers which control the entire.
Domain Name System:
1. Root Name Server - top-level server which contains entire DNS tree, maintained by ICANN. There are 13 servers.
2. Primary / Master Name Server - contains zone resource records. These records are updatable by domain name holders such as organizations.
3. Secondary / Slave Name Server - contains a copy of primary server files. This server has no authority to update, but reduce the workload of the master server by sharing the queries.

(i)  Name Servers are programs that run on a physical system and store all the zone data.
(ii) It provides to clients when queried by them.

There are two copies of zone files available, they are
1. Master file
2. Slave file.

Every zone has the server which contains a database called zone file.

India, Singapore, Srilanka

Each node in the DNS tree-like structure has a name, called a label. Label is a string having a maximum of 63 characters.

1. Name Space,
2. Name server,
3. Zone

Domain Name System (DNS) maintains all the directory of domain names/host names and help us to access the websites using the domain/host names.

A server can contain more than one zone files (Zones).

Zone can contain more than one sub domains.

Name server manages the database of domain names and corresponding IP addresses

Domain Name space is an entire collection Domains, Sub domains and Zones