The document explains the concept of DNS (Domain Name System) as a directory system that maps names to IP addresses for ease of use. It describes the organization of domain name space into hierarchical and float structures and outlines the different sections of domain space, including generic, country, and inverse domains. The document emphasizes the importance of unique names assigned to machines to prevent ambiguity and for security verification.

1.  What is DNS ?
 Name Space
 Domain Name Space
 DNS in The Internet

2.  To identify an each entity, TCP/IP protocol use the IP
address, which uniquely identifies the connection of a
host to the internet.
 However we prefer to use names instead of numeric
address to remember this numeric values easily.
 Therefore, to store this names assigned names, the
internet needs a directory system that can map a
name to an address.
 e.g. Telephone network.

3.  To be unambiguous, the names that are assigned to
machine must be unique because the addresses are
unique.
 Name Space can be organized in two ways
1. Float
2. Hierarchical

4. 1. Float name space : Name is a sequence of characters.
e.g. example.com
2. Hierarchical name space : Each name is made of
several parts.
• Each part is defined some particular criteria or
behavior of the organization.
e.g. news.example.com
support.example.com
download.example.com

5.  Domain name space is used for hierarchical name
space.
 A full domain name is a sequence of labels separated
by dots(.)
e.g. support.example.com
node(label) dot domain
• A full domain always reads from node up to the root.

6.  DNS is a protocol that can be used in different
platforms.
 The Domain Name Space was originally divided into
three different sections.
 Generic domains
 Country domains
 Inverse domains

7. • The generic domains define registered hosts
according to their generic behavior.

8. • First level of the generic domains section with tle
possible labels.

9. Country domain section uses two-character
1. Country abbreviations (e.g. .in for India)
2. Second label can be organizational or it can be more
specific national designations.
e.g. newsletter.gujarat.gov.in
behavior specific designation organization country

10. • Inverse domains is used to find the name of a host
when given the IP address.
e.g. 192.160.77.22 example.com
This concept is used only for the security
purpose to check whether IP and Name spaces are same
or redirect to any unreliable link.