How to change the SSH port on Linux

Changing the SSH port on Linux

1. Access the SSH configuration file: Open a terminal or an existing SSH connection and access the SSH configuration file. This file is usually located at /etc/ssh/sshd_config. You can open it with a text editor like nano.
   sudo nano /etc/ssh/sshd_config
   You will need superuser (root) permissions to edit this file.
   
   
2. Find the line specifying the port: Look for the line that starts with Port. By default, this line is usually commented out (preceded by #).
   #Port 22
   If it's already present and commented out, remove the # and change the port number (default is 22) to the new port you want to use. For example, to change it to port 2222:
   Port 2222
   If it's not present, you can add it at the end of the file.
   
   
3. Save the changes: Save the file after making the modifications. In nano, press Ctrl+O to save and Ctrl+X to exit.
   
   
4. Ensure the new port is allowed in the firewall: If you have a firewall enabled on your server, make sure to allow the new port.
   • For example, if you're using ufw on Ubuntu:
     sudo ufw allow 2222/tcp
     Replace 2222 with the port number you have configured.
     
     
   • If you are using a Red Hat-based distribution:
     sudo firewall-cmd --permanent --add-port=2222/tcp
     Replace 2222 with the port number you have configured. After adding the port, you need to reload the firewall for the changes to take effect.
     sudo firewall-cmd --reload
     
     
5. Restart the SSH service: To apply the changes, restart the SSH service. This can be done with the following command:
   sudo systemctl restart sshd
   If you're not using systemd, you can use:
   sudo service sshd restart
   
   
6. Verify the connection: Before closing the current session, open a new SSH connection specifying the new port to ensure everything is functioning correctly:
   ssh user@yourserver -p 2222
   Replace user with your username and yourserver with the IP address or hostname of your server.