What is IP Address?

An IP address, or Internet Protocol address, is a unique string of numbers assigned to each device connected to a computer network that uses the Internet Protocol for communication. It serves as an identifier that allows devices to send and receive data over the network, ensuring that this data reaches the correct destination.

Types Of IP address

IPv4

This is the most common form of IP Address. It consists of four sets of numbers separated by dots. For example, 192.158.1.38. Each set of numbers can range from 0 to 255. This format can support over 4 billion unique addresses. Here's how the structure is broken down

• Four Octets: Each octet represents eight bits, or a byte, and can take a value from 0 to 255. This range is derived from the possible combinations of eight bits (2^8 = 256 combinations).

• Example of IPv4 Address: 192.168.1.1

  • 192 is the first octet

  • 168 is the second octet

  • 1 is the third octet

  • 1 is the fourth octet

Each part of the IP address can indicate various aspects of the network configuration, from the network itself to the specific device within that network. In most cases, the network part of the address is represented by the first one to three octets, while the remaining section identifies the host

IPv4 Address Format

185 . 107 . 80 . 231

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| Octet | | Octet | | Octet | | Octet |

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Binary Representation: 10111001 . 01101011 . 01010000 . 11100111

Each octet = 1 byte = 8 bits Total: 4 bytes = 32 bits

IPV 6

IPv6 was created to replace IPv4 because we were running out of IP addresses. Unlike IPv4, which uses 32 bits, IPv6 uses 128 bits, allowing for a much larger number of addresses. An IPv6 address is written as eight groups of four hexadecimal numbers, separated by colons (:).
Each group (like 2001, 0db8, 85a3, etc.) represents 16 bits of the total address.

Example:

2001:0db8:85a3:0000:0000:8a2e:0370:7334

What is Server?

A server is a special computer that stores and shares information or services with other computers.

Why Do We Use and Need Servers?

• Open websites (Google, YouTube, etc.)

• Send and receive emails

• Store and access files

• Run apps like games, banking, or shopping

Use cloud services (like AWS, Google Cloud)

Why are Servers Important?

• Without servers, there would be no internet, no websites, no apps.

They help us connect, share, and work online.

Elastic IP

An Elastic IP is a permanent public IP address that you can use for your EC2 server in AWS.

Why We Use Elastic IP

• To have a fixed address to access your server.

• So your website or app is always reachable at the same IP.

• You can move it to another server if needed.

• You get 1 free Elastic IP (only if it's being used).

AWS charges you if you reserve it but don’t attach it to anything.

What is an EC2 Instance?

An EC2 instance is a virtual computer you can create and use on the internet using AWS. EC2 stands for Elastic Compute Cloud.

Why We Use It

• To run websites and apps

• To practice coding

• To store data

To use a computer from anywhere

What is the PEM file or Key file used for when creating an EC2 instance?

When you create (launch) an EC2 instance, AWS asks you to create or choose a key pair.
This key pair gives you a PEM file which is your private key.

Why Do You Need It?

• It’s used to log in securely to your EC2 instance using SSH.

• Without it, you can’t access your instance from your computer.

• It protects your server so that only you can log in.

  How You Use It

  After the instance is created, you run a command like this in your terminal:

  ssh -i my-key.pem ec2-user@your-instance-ip

• Download the PEM file once and keep it safe AWS won’t let you download it again!

• If you lose it, you can’t connect to your EC2 instance.

Keep it private and set permissions

Security Groups

An AWS Security Group is like a firewall for your EC2 instance.
It controls who can connect to your server and what they can do.

Why We Use Security Groups

• To protect your instance from unwanted access

• To allow only trusted traffic

• To open specific ports for specific tasks (like port 22 for SSH, 80 for websites)

How It Works:

You set inbound rules and outbound rules

Common AWS Port Rules (Inbound)

• Outbound rules are usually open by default in AWS (allowing all traffic out).

You can restrict them if you want more control and security.

Steps to Launch Your First EC2 Instance

1. Go to EC2 Dashboard

• Login to AWS → Search for EC2 in the search bar.

• Click on EC2 → Click “Launch instance”.

  

  2. Name Your Instance

  • Give your instance a name (e.g., myfirstinstance)

3. Choose AMI (Operating System)

• Choose Amazon Linux 2 or Ubuntu (free tier eligible)

  

  4. Choose Instance Type

  • Pick t2.micro → (Free tier eligible and good for beginners)

    

    5. Create or Choose a Key Pair (PEM File)

    • If you don’t have a key pair:

      • Click Create new key pair

      • Name it something like my-key

      • Choose .pem

      • Click Download key pair and save it safely on your PC

    • You’ll use this file later to log in to your instance

      

      6. Set Security Group (Firewall Rules)

      • Create a new security group:

        • Allow SSH (port 22) → Source: My IP (recommended)

        • Allow HTTP (port 80) if you're hosting a website

This decides who can access your instance

7. Launch the Instance

• Review settings → Click Launch Instance

• Wait a few seconds

  

8. Connect to the Instance

• Go to Instances → Select your instance

• Click Connect

Conclusion of Today’s AWS Learning

AWS Security Groups & Ports

• Security Group is like a firewall that protects your server.

• It controls who can access your EC2 instance and on which ports.

• Important ports to remember:

• 22 – for SSH (to log in to Linux)

• 80 – for websites (HTTP)

• 443 – for secure websites (HTTPS)

Always limit SSH to your IP for safety

Launching an EC2 Instance:

• EC2 is like a computer in the cloud.

• You can choose the OS, size, and setup.

• You need a PEM/key file to connect it’s your secret key.

• After launching

• You can log in using SSH.

Start using it like a normal server (host a site, run code, etc.)

IP Address And Elastic IP

• An IP address is like your server’s home address on the internet.

  • There are two types:

    • IPv4 – Common, shorter (like 192.168.1.1)

    • IPv6 – Newer, longer, supports more devices

  • An Elastic IP is a permanent public IP that you can attach to your EC2 instance, so it doesn’t change.