Find code and diagrams at: www.EliTheComputerGuy.com
UFW is a simple firewall application that is included with Ubuntu nd can be installed on other distributions of Linux.
Note: For the demonstrations to work you may need to change settings or hardware configurations within your virtualization software. I had to connect my host machine to a hard word connection for Rules for specific IP Addresses to work.
sudo ufw status - shows current status of ufw
sudo ufw enable - Enables ufw firewall
By default ALL incoming traffic is blocked
sudo ufw disable - Disables ufw
sudo ufw status verbose - Shows all Rules currently configured for ufw
sudo ufw allow 21 - Allows specific port
sudo ufw allow ssh - Allows ports for a specific service
sudo ufw status numbered - Shows rules in numbered order so that you can delete specific rules
sudo ufw delete 1 - Deletes rule based on number
sudo ufw allow from 192.168.1.2 - Allows traffic from a specific IP address to all ports
sudo ufw allow from 192.168.1.0/24 - Allows traffic from a subnet to all ports
sudo ufw allow from 192.168.1.2 to any port 22 - Allows traffic from a specific IP address to a specific port
sudo ufw allow from 192.168.1.0/24 to any port 22 - Allows traffic from a subnet to a specific port
sudo ufw reset - Deletes all rules and disables ufw