How to Connect to an AWS EC2 Instance Easily

To connect to an EC2 instance, use ssh with your private key and the instance's public IP address like ssh -i your-key.pem ec2-user@public-ip. Make sure your security group allows SSH (port 22) access from your IP.

Syntax

The basic command to connect to an EC2 instance via SSH is:

ssh -i <path-to-private-key> <user>@<public-ip-address>

Here:

• -i <path-to-private-key>: Specifies the path to your private key file (.pem) downloaded from AWS.
• <user>: The username depends on the instance OS (e.g., ec2-user for Amazon Linux, ubuntu for Ubuntu).
• <public-ip-address>: The public IP or DNS of your EC2 instance.

bash

ssh -i /path/to/my-key.pem ec2-user@203.0.113.25

Example

This example shows how to connect to an Amazon Linux EC2 instance using SSH with a private key file named my-key.pem and the instance's public IP 203.0.113.25.

bash

chmod 400 my-key.pem
ssh -i my-key.pem ec2-user@203.0.113.25

Output

Warning: Permanently added '203.0.113.25' (ECDSA) to the list of known hosts.
[ec2-user@ip-203-0-113-25 ~]$

Common Pitfalls

• Incorrect permissions on the private key file: The key file must have restricted permissions (use chmod 400).
• Wrong username: Use the correct user for your instance OS (e.g., ec2-user, ubuntu, admin).
• Security group blocking SSH: Ensure port 22 is open for your IP in the instance's security group.
• Using the wrong IP address: Use the public IP or public DNS, not the private IP, unless connected via VPN or inside the same network.

bash

Wrong:
ssh -i my-key.pem root@203.0.113.25

Right:
ssh -i my-key.pem ec2-user@203.0.113.25

Quick Reference

Keep these tips in mind when connecting to EC2:

• Use chmod 400 on your private key file.
• Match the username to your instance OS.
• Check security group rules allow SSH from your IP.
• Use the instance's public IP or DNS name.

Key Takeaways

Use SSH with your private key and the correct username to connect to EC2.

Set private key file permissions to 400 to avoid SSH errors.

Ensure security groups allow inbound SSH (port 22) from your IP address.

Use the instance's public IP or DNS, not the private IP, for connection.

Match the SSH username to the EC2 instance's operating system.