Prerequisites

To connect to an EC2 instance, you need three things:

• PEM file — The key pair downloaded during EC2 launch
• Public IP — The public IPv4 address of the EC2 instance
• Username — Depends on the OS/AMI used

Default Usernames by OS

Method 1: SSH on Windows (Git Bash / PowerShell)

Windows 10/11 has SSH built-in. You can also use Git Bash.

Steps:

# Step 1: Navigate to where your PEM file is saved
cd Downloads

# Step 2: Set correct permissions (recommended)
chmod 400 your-key.pem

# Step 3: Connect
ssh -i your-key.pem ubuntu@<EC2-Public-IP>

Real example:

ssh -i mykey.pem ubuntu@13.235.45.67

Command breakdown:

Method 2: SSH on Linux / macOS

Steps: