The presentation introduces DNS (Domain Name System), including its history, components, services, and working mechanism. DNS is a large distributed database that maps hostnames and domain names to IP addresses. It originated as a central HOSTS.TXT file maintained by NIC but grew too large, leading Paul Mockpetris to develop the first DNS specification in 1984. DNS has a global, hierarchical structure with name servers, resolvers, and a namespace database to provide services like address translation and load distribution through both iterative and recursive queries.

1. Presentation on Domain Name
System
Presented by:
Sarita Neupane
Sarita Gyawali
Jyoti Aryal

2. Contents
 Introduction
 History
 Features
 Components
 Services
 Working mechanism

3. Introduction
 DNS is basically a large database that resides on
various computers and contains
 name and IP address of various hosts on the internet
and various domains
 Used to provide information when the queries are
made

4. History
 ARPANET utilized a central file HOSTS.TXT
-contains name to address mapping
-Maintained by SRI’s-NIC(Standford research institute-Network
Information Centre)
 Administrators mail changes to NIC
-NIC updates HOSTS.TXT
 As the system grew HOSTS.TXT had problem
 In 1984 Paul Mockpetris released the first version
 Internet Engineering Task Force(IETF) published original specification in
RFC-882 and RFC 883)

5. DNS Features
 Global distribution
shares the load and administration
 Loose coherency
geographically distributed but still coherent
 Scalability
can add DNS servers without affecting the entire DNS
 Reliability
 Dynamicity
modify and update data dynamically

6. Components
I. Namespace
Database like space that contains all information
II. Servers
making the namespace available for client
I. Resolvers
hosts that will make query to the servers about particular namespace

7. Hierarchy of DNS servers

8. DNS services
 Translating hostname or domain name to IP address
 Host aliasing
 Mail server aising
 Load distribution

9. Working Mechanism
 Iterative method
when the name server of a host cannot resolve a query it sends
referral to other server to the resolver
 Recursive method
the name server issues a query to resolve the query

10. Working Mechanism :Iterative query

11. Working mechanism : Recursive query

12. Working Of DNS

13. Thank you!!!!