How to Fix AWS EC2 SSH Connection Refused Error

In this tutorial, you'll learn about How to Fix AWS EC2 SSH Connection Refused Error. We cover key concepts, practical examples, and best practices to help you understand and apply this topic effectively.

You try to SSH into your EC2 instance and get Connection refused or Operation timed out — the instance is not accepting SSH connections.

Step-by-Step Fix

1. Check security group inbound rules

aws ec2 describe-security-groups --group-ids sg-12345678

Look for SSH (port 22) in the output:

{
    "IpPermissions": [
        {
            "FromPort": 22,
            "ToPort": 22,
            "IpProtocol": "tcp",
            "IpRanges": [{"CidrIp": "0.0.0.0/0"}]
        }
    ]
}

2. Add SSH inbound rule if missing

aws ec2 authorize-security-group-ingress --group-id sg-12345678 --protocol tcp --port 22 --cidr 0.0.0.0/0

3. Verify the key pair

ssh -i ~/.ssh/my-key.pem ec2-user@54.123.45.67 -vvv

Expected output on success:

debug1: Authentication succeeded (publickey).
debug1: channel 0: new [client-session]

4. Check instance status

aws ec2 describe-instance-status --instance-ids i-12345678

Expected output:

{
    "InstanceStatuses": [
        {
            "InstanceId": "i-12345678",
            "InstanceState": {"Name": "running"},
            "SystemStatus": {"Status": "ok"},
            "InstanceStatus": {"Status": "ok"}
        }
    ]
}

5. Fix key permissions

chmod 400 ~/.ssh/my-key.pem

6. Check network ACLs

aws ec2 describe-network-acls --filters Name=association.subnet-id,Values=subnet-12345678

Ensure inbound/outbound rules allow port 22 traffic.

Common Mistakes

Prevention

• Use EC2 Instance Connect for browser-based SSH.
• Restrict SSH access to your IP address only.
• Use Systems Manager Session Manager for password-less access.
• Keep security group rules minimal.

Common Mistakes with ec2 ssh

1. Misunderstanding that String is [Char] with poor performance for large text operations
2. Using foldl instead of foldl' causing stack overflow on large lists
3. Forgetting deriving (Show, Eq) on custom data types needed for debugging

These mistakes appear frequently in real-world AWS code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ