Using UFW, the uncomplicated firewall on Ubuntu 12.04

It is normal in Linux for the iptables module to control what we know as the firewall and this remains the case with UFW. UFW provides, perhaps, a more simple command line interface to iptables and application profiles that relate to your services. For instance, if I want to control the ports used by SAMBA I can use the application profile for SAMBA without having to know about the ports that is uses.

UFW ships with Ubuntu but is not enabled. We can start by enabling it:

sudo ufw enable

This will both enable the service and enable it for auto-start, we can query the service with :

sudo ufw status

or

sudo ufw status verbose

if we want a listing of what is allowed or denied. from the latter we can see the once enabled the firewall enables outgoing traffic only by default. This just leverages iptables and we can view the iptable status with

iptables -L

To enable a service we could use the command :

sudo ufw allow 22

if we wanted to permit SSH, id the application needed more ports we could use an Application profile :

sudo ufw app list

will display the current profiles and

sudo ufw allow Samba

will permit the ports for Samba