How to enable and disable the firewall on Ubuntu 16.04
The UFW firewall is the default firewall that ships standard with the Ubuntu Linux Distribution. UFW stands for Uncomplicated Firewall.
To enable the UFW firewall, open a new Terminal window and execute the following command:
sudo ufw enable
To disable the UFW firewall, open a new Terminal windows and execute the following command:
sudo ufw disable
To view the status of the UFW execute the below command:
sudo ufw status
More can be read about the UFW firewall on the Ubuntu wiki. Click here to read more.