In This Chapter
Building a firewall
Starting your firewall
Your newly installed Ubuntu desktop computer is quite network safe. Ubuntu, out of the box, doesn't run any unnecessary, network‐aware services;
network‐aware services are
processes (running programs or applications) that respond to network connections.
Network services that don't exist can't be hacked. This is a good thing.
However, Ubuntu supplies a firewall configuration utility because life changes. As you use your computer, you'll probably want to change and modify it. Changing and modifying might introduce new network services, and those services need to be protected with a firewall.
Firewalls limit access to and from networks and are generally used to prevent unwanted incoming connections, especially ones from the Internet.
In the past, firewalls were absolutely necessary because Linux distributions installed and activated many network‐aware services by default. They installed the proverbial kitchen sink. Most people didn't need the services — or the sink — but someone always did. Vendors turned services on in order to make as many as possible of their customers happy.
Well, as the adage says, you can please some of the people all of the time, but . . . well, you get my drift. Turning on services was very bad from a security standpoint. Some services were poorly configured, some were buggy, and hackers went to town. ...