Before I get into why you actually need a firewall, I think it’s important that you know what a firewall even is. In its simplest form, a firewall is a piece of software or hardware that filters all incoming traffic (and sometimes outgoing) to a network or computer from the internet. As network traffic passes through the firewall, the firewall decides whether or not to forward the traffic on to your network, based on the rules and exceptions defined by you. To see a list of some of the most common features of all firewalls, read my other tutorial, Firewall Features and Their Uses.

So now that you know what a firewall does, let’s talk about why it does all this filtering. Now, I hate to break it to you, but for those of you who think that nobody is out to get you, and that the internet is safe, you are 100% incorrect. Each day, millions of people are inadvertently infected with malicious software, such as viruses, worms, malware, spyware, etc. These programs can do anything from crippling your new computer to stealing your bank passwords. But wait, it gets worse! Each day thousands more of these malicious programs are created! At this point, you may be wondering: Who in their right mind would create such atrocities? Well, we have a name for these malicious people: Hacker. And while I may not be able to explain to you why hackers do what they do, one thing is for sure. You must protect yourself from them.

Now, as If I haven’t scared you into getting a firewall yet, I will present some situations that may have been prevented with a properly configured firewall.

Keep in mind as your reading this that the best way to estimate something’s worth is to look at the cost of its loss.

1. You own your own business, and rely heavily upon the staff members at your disposal. You are on your way to work, and upon getting to your office, you find out that your network has been compromised, and substantial damage has been done. It will take your staff hours, and possibly days, to restore and fix everything. The more time they spend fixing your network is more money lost.

2. You are a government worker who has been given a laptop with sensitive information regarding thousands of social security and personally identifiable information. While at home, you connect your laptop to your home network, and while you go to use the bathroom, your network was attacked. You quickly login to your computer to find that all that sensitive information was stolen. Innocent people’s financial lives are now in the hands of an outlaw, and it is entirely your fault, you realize miserably.

3. You have just taken your family on the trip of a lifetime and came home with thousands of photos. You eagerly load them onto your computer, and put them into storage. Weeks later you are looking for these photos and can’t seem to find them. You call your computer tech support, thinking it might be a hard drive problem, they inform you that your computer security was most likely compromised, and all you’re once in a lifetime photos were removed. Now you have got nothing to remind you of the amazing time you had.

4. You have just started your own online home business. You are extremely optimistic, and are going on the local news station in a half hour to promote it. You are ready to leave, but you want to check out your website to make sure everything is just right for its promotion. You open your web browser, type in the URL in the address bar, and to your dismay, find your site is unavailable. You’ve run out of time, but on the way to the news station, you call up your web hosting tech support, and they tell you your site was one of many sites to be attacked. They tell you the down time will likely last for a couple of more hours until they get your service restored. As you pull into the parking lot, you are racking your brains trying to think of what to tell the newscasters and the audience.

5. You have just bought a brand new computer. You come home, set it up, and connect it to your new home network. You haven’t taken time to secure your network, and you are about to go on a short trip. You leave, and forget to turn your newly-bought computer off. A couple days later, you come home to find your new computer totally wrecked. The operating system was destroyed, and your computer will have to be restored by a qualified technician: more money out of your wallet. A couple days later the FBI show up at your door and politely inform you that your computer was recently used for illegitimate purposes. You try to explain that it wasn’t your fault, but they have already received a warrant to take you into custody.

Now that I have convinced you that you do need a firewall, read my next tutorial in the series: What Type of Firewall is For You.