Scribd
Upload
506 views18 pages

Domain Name System

This document discusses the domain name system (DNS) which provides a hierarchical and distributed database that stores information for mapping domain names to IP addresses. It describes the domain name space structure, domain name labels, types of domain names, DNS server hierarchy including root, primary and secondary servers, DNS resolution process using recursive and iterative queries, DNS message formats, and key components like the DNS header. The document also outlines generic and country-specific domain name categories.

Uploaded by

Dinesh Kumar
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPT, PDF, TXT or read online on Scribd
506 views18 pages

Domain Name System

This document discusses the domain name system (DNS) which provides a hierarchical and distributed database that stores information for mapping domain names to IP addresses. It describes the domain name space structure, domain name labels, types of domain names, DNS server hierarchy including root, primary and secondary servers, DNS resolution process using recursive and iterative queries, DNS message formats, and key components like the DNS header. The document also outlines generic and country-specific domain name categories.

Uploaded by

Dinesh Kumar
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPT, PDF, TXT or read online on Scribd
You are on page 1/ 18

Chapter 25.

Domain Name System


25.1 25.2 25.3 25.4 25.5 25.6 25.7 25.8
Fall 2006

Name Space Domain Name Space Distribution of Name Space DNS in the Internet Resolution DNS Message DDNS Encapsulation
Computer Networks 25-1

Domain name space


Flat name space, Hierarchical name space

Fall 2006

Computer Networks

25-2

Domain names and labels

Fall 2006

Computer Networks

25-3

FQDN and PQDN


FQDN (Fully Qualified Domain Name) PQDN (Partially Qualified Domain Name)

Fall 2006

Computer Networks

25-4

Domains
Domain: Subtree of the domain name space

Fall 2006

Computer Networks

25-5

Hierarchy of name servers

Fall 2006

Computer Networks

25-6

Zones and domains


Zone: What s server is responsible for, or has authority over

Fall 2006

Computer Networks

25-7

Root Server
A root server is a server whose zone consists of the whole tree.

Primary and Secondary Servers


A primary server loads all information from the disk file; the secondary server loads all information from the primary server.

Fall 2006

Computer Networks

25-8

DNS in the Internet

Fall 2006

Computer Networks

25-9

Generic domains
Generic domains define registered hosts according to their generic behavior Each node in the tree defines a domain, which is an index to the domain name space database.

Fall 2006

Computer Networks

25-10

Generic domain labels


Label com edu Description Commercial organizations Educational institutions

gov
int mil net org

Government institutions
International organizations Military groups Network support centers Nonprofit organizations

Fall 2006

Computer Networks

25-11

New generic domain labels


Label
aero biz coop

Description
Airlines and aerospace companies Businesses or firms (similar to com) Cooperative business organizations

info
museum name pro
Fall 2006

Information service providers


Museums and other nonprofit organizations Personal names (individuals) Professional individual organizations
Computer Networks 25-12

Country domains

Fall 2006

Computer Networks

25-13

Inverse domain

Fall 2006

Computer Networks

25-14

Resolution
Name-address resolution: a name to address/an address to a name Resolver: DNS client called by a host Recursive resolution and iterative resolution

Fall 2006

Computer Networks

25-15

Iterative resolution

Caching
Fall 2006 Computer Networks 25-16

Query and response messages


DNS has two types of messages

Fall 2006

Computer Networks

25-17

Header format

Fall 2006

Computer Networks

25-18

You might also like