README.md

Blocked SSH port after configuration on AWS Lightsail

Issue description

The server cannot be reached through the selected SSH port after changing it on the sshd_config file and enabled on UFW settings

Basic task step by step

Install Apache engine

1. Update all currently installed packages

   sudo apt-get update
   sudo apt-get upgrade
   

2. Change the SSH port from 22 to 2200

   • Use sudo nano /etc/ssh/sshd_config and then change Port 22 to Port 2200 , save & quit.
   • Reload SSH using sudo service ssh restart

3. Configure the Uncomplicated Firewall (UFW)

   • Configure the Uncomplicated Firewall (UFW) to only allow incoming connections for SSH (port 2200), HTTP (port 80), and NTP (port 123)

   sudo ufw allow 2200/tcp
   sudo ufw allow 80/tcp
   sudo ufw allow 123/udp
   sudo ufw enable 
   

Extra step to enable on AWS panel

⚠️ If you still cannot access the instance after making the changes run the following steps

1. Open the AWS panel on https://lightsail.aws.amazon.com/

2. Click on the instance details, it will redirect you to something like: https://lightsail.aws.amazon.com/ls/webapp/us-east-1/instances/Ubuntu-512MB-Virginia-1/

3. Now select the Network tab

4. Click on the Add another button on the bottom left

5. Select Custom on application column, TCP, and 2200 on the following

6. Reboot the machine

Folders and file infos #### AWS panel configuration

Instance SSH connections working

Related issues

If you block the SSH port on UFW BEFORE changing the sshd_config file, you can create a deadlock, which is pretty much irreversible, check some links below to get general help on how to save time recreating the instance

• https://stackoverflow.com/questions/41929267/locked-myself-out-of-ssh-with-ufw-in-ec2-aws <- This one shows how to perform a recovery on AWS instances, so you would not lose all of your work