Adjusting the Firewall under Ubuntu

The default firewall configuration tool for Ubuntu is ufw. Developed to ease iptables firewall configuration, ufw provides a user friendly way to create an IPv4 or IPv6 host-based firewall. By default UFW is disabled.

Enable or Disable

To turn UFW on with the default set of rules:

sudo ufw enable

To check the status of UFW:

sudo ufw status verbose

To disable ufw use:

sudo ufw disable

To Allow SSH Connections from a specific or range of IP Addresses:

sudo ufw allow from 123.123.123.123 to any port 22 proto tcp

sudo ufw allow from 123.123.123.0/24 to any port 22 proto tcp