EC2 Instance connect allows one to connect EC2 instance directly from browser. If you are trying from command line or putty and experiencing issues.. please see below cases.
Case-1: Connection timed out.
If your EC2 instance is running and trying to SSH with correct IP (there will be a change in IP after each restart), there must be a security group issue. Any timeout is related to security group or a firewall, ensure your security group is correct (port, protocol, source IPs etc) and assigned to the EC2 instance.
If there is still a connection timeout issue, it means a corporate firewall, or a personal firewall is blocking the connection. Please use EC2 instance connect.
Case-2: Connection refused.
- It means the EC2 instance is reachable but SSH utility is not running. Please install SSH client on your local machine and try again.
Case-3: Permission denied (publickey,gssapi-keyex,gssapi-with-mic)
- This means either three things:
- You are using wrong security key or not using a security key. Please look at your EC2 instance configuration to make sure you have assigned the correct key to it.
- You are using wrong user. Please try with ec2-user.
- Key file permissions are incorrect. Please change it to 0400 (in case of Windows, please ensure nobody else has any level of access to the file except you).
Case-4: No supported authentication methods available (server sent: publickey, gssapi-keyex,gssapi-with-mic) error when trying from Putty.
This happens when you do not use key in .ppk format.
- Open PuTTYgen -> Go to File -> Load private key and open “.pem” file.
- Save private key in “.ppk” format.
- Now, load your session in putty (ec2-user@IP) -> SSH -> Auth -> browse private key which you just saved and hit open, you should be all set and logged onto EC2 instance.