This little tool allows you to set up a
basic firewall on your machine. It filters connection attempts
made from the outside, and blocks unauthorized ones. It's a good
idea to run it just after installing your
machine and before connecting to the
Internet, therefore minimizing the risks of your machine being
compromised.
This Wizard consists of the steps we detail below.
Open Up Ports, If Needed. If checked, uncheck the Everything (no firewall) box, and then check the boxes corresponding to the services you wish to make available to the outside world. If you wish to authorize a service which isn't listed here, click on Advanced to manually enter the port numbers to open.
![[Tip]](images/tip.png)
This Won't Block You from Accessing the Net. Not checking a service in this list won't stop you from connecting to the Internet. It will only prevent people from the Internet connecting to that service on your machine. If you don't plan on hosting any services on your machine (common case for a desktop machine) just leave all boxes unchecked.
How to Disable the Firewall. On the other hand if you wish to disable the firewall and leave all services accessible from the outside, check Everything (no firewall), but please bear in mind that this is very insecure, and therefore not recommended.
Stay Informed of Connections on your Machine. 
The interactive
firewall can warn you of connection attempts on your machine by
displaying alert popups through the network applet. Check the
Use Interactive Firewall option to activate this
feature.
- Port scan detection
Activate this option to be warned of malicious attempts to access your machine.
- Other entries corresponding to open ports
Next you are shown a checkbox for each port you have chosen to open during the previous step. Activating them will popup a warning each time a connection attempt is made on those ports.
The next step consists of selecting the network interface connected to the Internet.
If you don't know which interfaces you have connected for the Internet, you can check the system network configuration (see Section 1.3, “Reconfiguring Interfaces”). You can finally click to install the required packages, activate the firewall and enjoy your secure Internet connection.