Use AWS Systems Manager Session Manager

1. Open the AWS Systems Manager console.
2. Start a session.

3. To disable firewalls and restart the SSH service, run the following commands.
   sudo iptables -F
   sudo service sshd restart

4. Verify that the SSH tcp port (22) is in a listening state.

   sudo netstat -tnlp | grep :22
   tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      849/sshd
   tcp6       0      0 :::22                   :::*                    LISTEN      849/sshd
   

5. Terminate the session.
6. Connect to the instance using SSH.