🔐 What is a Security Group?
A Security Group (SG) acts as a virtual firewall that controls inbound and outbound traffic for your virtual machine (EC2 instance).
Works at instance level
Stateful (return traffic is automatically allowed)
Supports Allow rules only
🛠️ Steps to Create a Security Group in AWS
1️⃣ Sign in to AWS Console
Go to AWS Management Console
Navigate to: Services → EC2 → Security Groups
2️⃣ Click "Create Security Group"
Fill in the details:
Security group name → (e.g. datacenter-sg)
Description → Allow SSH and HTTP access
VPC → Select your VPC
🔽 Configure Inbound Rules
Click Add Rule and configure:
Use My IP instead of Anywhere for SSH.
Avoid opening port 22 to the whole internet.
🔼 Configure Outbound Rules
Default rule allows All traffic
Usually no changes needed
3️⃣ Click Create Security Group
Your Security Group is now ready.
🔗 Attach Security Group to EC2 Instance
1. Go to EC2 → Instances
1. Select your instance
1. Click Actions → Security → Change security groups
1. Select your new SG
1. Click Save
🎯 Result
SSH access controlled
Web traffic allowed
Instance protected by firewall rules
Secure and production-ready configuration
📚 Additional Guides
🔁 Modify existing Security Group
🚫 Restrict SSH to corporate IP
🏗️ Production-level security group architecture
☁️ Azure NSG version of this guide