DOMAIN NAME SYSTEMS IN NETWORKS

1. DNS

2. DEFINITION
DNS stands for Domain Name Service which
converts Domain Names into IP Address.

3. Why do we go for DNS

4. HOW DNS WORKS

5. Rules for Domain Name
1) Each Label (i.e.) Domain Name (.com, .edu,
.in) should not exceed 63 Characters.
2) The full domain name should not exceed 253
Characters (www.twitter.com)
3) The Domain Names are Case Independent
one (It can either Upper Case (or) Lower Case
Letters).

6. Rules for Domain Name
4) The Domain Name can be Letters, Digits,
Hyphen (www.kcet123-vnr.org). This is called
LDH Rule.

7. PROPAGATION PERIOD
The time taken for registering a domain on the
DNS Server takes 12-36 hours for the domain
name should be accesses world wide.
This time period is called Propagation Period

8. World famous registers for Domain
Names
1) GoDaddy.com
2) Name cheap.com
3) 1&1 Internet.com
4) Dotster.com

9. DNS SERVICES
Host Name into IP Address translation

10. DNS SERVICES
(For Ex.) Google is accessed by most number of
People in the world. So Google have some ‘N’
Number of IP Address 174.12.33.44,
174.12.33.45, 174.12.33.46, 174.12.33.47

11. REVERSE LOOKUP
It is defined as Multiple domain names can be
associated with an IP Address
(For Ex.) 1.2.3.4 is associated with a Domain
Name called www. Red.in
The same 4.3.2.1 can be mapped to www.
Tnpsc.com

12. CURRENT IMPLEMENTATION OF DNS

13. EXAMPLE