ufw stands for Uncomplicated Firewall.
If ufw is not installed in the system, then install it with the command:
sudo aptitude install ufw
The command activates ufw in the system, it will also be included every time the system starts:
sudo ufw enable
If ufw does not start after restarting the system, then edit ENABLED=no to ENABLED=yes in the file:
sudo nano /etc/ufw/ufw.conf
To disable is used:
sudo ufw disable
Deny all incoming connections:
sudo ufw default deny
To allow access for a subnet or address:
sudo ufw allow from 10.0.0.0/24
To re-enable all incoming connections:
sudo ufw default allow
Permit SSH connection from outside:
sudo ufw allow ssh
An example of allowing access to a specific port:
sudo ufw allow 80/tcp
View status:
sudo ufw status sudo ufw status verbose
Disable logging:
sudo ufw logging off
View profiles for applications:
sudo ufw app list
The configuration files are in /etc/default/ufw and /etc/ufw/applications.d
View official documentation:
man ufw
See also my article – Configure IPTables