Lec-03.md

How the Internet Works

What is internet?

:)) Inter => Interconnected , net => Network :)) Network of Networks

DNS : Domain Name System : can convert the request into IP address

IP : Internet Protocol

Client-Server Model

:)) client send different types request i.e get,put,post,delete to server after some preprocessing step server can send response to the client.

ISP : Internet Service Provider

Packets : Data can be divided into small small chunks or units that unit/chunks is called packets

Protocol Stack :

1 Application layer : protocol can be used for specific application

2 TCP layer : This layer can give me the PORT no

3 IP Layer : Add IP address of Destination machine

4 Hardware

Protocol : set of rules

HTTP : Hyper Text Transfer Protocol

FTP : File Transfer Protocol

SMTP : Simple mail transfer protocol

Gmail can use SMTP Protocol : simple mail transfer protocol

Router : Connect Multiple Network

TCP/IP Model

OSI Model

Physical Layer

Data Layer

Network Layer

Transport Layer

Session Layer

Persentation Layer

Application Layer

H.W : Write a command for print the ip address of www.google.com

Sol : To print the IP Address of the google.com you can use the command "nslookup" in a terminal or command prompt

nslookup www.google.com , This command will query the DNS server and return IP Address associated with the hostname "www.google.com".

H.W : Describe IP Address i.e IPv4 IPv6

An IP address is a unique numerical identifier assigned to each device connected to a computer network that uses the internet protocol for communication.

IP address are typically repersented as a series of four numbers separted by dots, such as 192.168.0.1. Each of four numbers can range from 0 to 255.

IPv4 : It is the older and more widely used protocol, but it has limitations in the number of available addressess.

IPv6 : It provides a much larger address space and is designed to address the limitations of IPv4.