Your Shell works exactly like a regular server when it comes to security. You may use the firewall within the operating system to apply protection.
- The default firewall configuration tool for Ubuntu is ufw.
To enable a firewall in Ubuntu Shell, type the following in a terminal:
sudo ufw enable
Open ssh port (22 by default):
sudo ufw allow 22
Allow access from specific hosts or networks to a port:
sudo ufw allow proto tcp from *source ip* to *destination ip* port *port number*
Checking UFW Status and Rules:
sudo ufw status verbose