Basic Ubuntu Linux Firewall Configuration
A firewall is a vital component in protecting a computer system, or network of computers from external attack (typically from an internet connection). Any computer connected directly to an internet connection must run a firewall to protect against malicious activity. Similarly, any internal network must have some form of firewall between it and an external internet connection.
This chapter will cover the steps necessary to configure an Ubuntu Linux firewall.
Ubuntu Linux Firewall Options
Ubuntu Linux provides two firewall configuration options. The first is a basic yet effective and easy to use firewall configuration system called lokkit. Another, more advanced, option is called GuardDog.
In this chapter we will explore lokkit and in the next chapter (Installing and Configuring a GaurdDog Firwewall on Ubuntu) we will look at the GaurdDog firewall in more detail.
Configuring a Basic Ubuntu Linux Firewall
The lokkit tool is not installed by default on Ubuntu Linux so before we can begin to configure a firewall we first need to install the appropriate package. There are two ways to do this, either using the Linux command-line, or using the Synaptic Package Manager. We will begin by looking at the Synaptic Package Manager method.
To launch the Synaptic Package Manager click on the System menu on the desktop and select "Synaptic Package Manager from the Administration sub-menu. Enter your password when prompted to do so. The Synaptic Package Manager will appear as follows:
Once the package manager has loaded the next step is to locate the package we need to install. Click on the Search button the the Synaptic toolbar, enter lokkit in the Search dialog and press Search. The search should return two results, lokkit and gnome-lokkit. lokkit is a text based version of the tool and gnome-lokkit is a graphical version. gnome-lokkit requires that lokkit also be installed so click on the check both next to gnome-lokkit and select Mark for installation from the drop down menu. A dialog appears stating that lokkit also needs to be installed. Click on the Mark button to also install lokkit.
Now that we have defined what we want to install we now need to installed it. Do do so simply click on the APply button located in the Synaptic toolbar and click Apply in the Summary dialog. The package manager will now download and install the tweo packages. Close the completion dialog and exit Synaptic once the installation is finished.
