How Firewalls Work

In this age of practical dependence upon computers to facilitate our jobs and lives, you’ve probably heard firewalls mentioned from time to time. Even if you don’t know the exact science behind them, the idea is that firewalls are so named because they separate your computer from the metaphorical fire that roams the wide-open plains of the internet. Of course, that’s just hyperbole, but a firewall essentially acts as a semi-permeable barricade that allows information to leave and enter your computer system, but only if that information is deemed safe to pass through the pre-set filters.

Basically, a firewall works like this. Let’s say you have more than one device that is capable of accessing the internet in your home or office. If you're a manager, you want to ensure that your employees aren’t just goofing off on video-game sites all day. To do so, you program your company's firewall to block access to video-game sites.

I’m sure we’ve all been at work and attempted to use our internet connections to access a site that our employers have blocked. Although it’s difficult to say why your company feels that lolcats.com is a threat, it does. So what exactly is blocking you from accessing that website at work? That’s the firewall.

Now, the cool thing about firewalls is that they are extremely customizable. If we’re talking about a company with dozens to hundreds of employees, the IT department can manipulate the company's firewalls to allow a wide range of information to pass through while rejecting specific information. They can even program the firewall to block access to sites that contain certain words or phrases, although it generally has to be an exact match. A firewall won’t block sites with the word “videogames” if you set it to block sites with the words “video games.”

So why use firewalls at all? Doesn’t antivirus software provide enough protection? Well, yes and no. Firewalls provide a high level of customization that allows you to regulate how the people in your home or business interact with the internet. They are a valuable tool that is often free of charge.

In a best-case scenario, a firewall should be the first line of defense and should be supplemented by quality antivirus software. Some firewalls can even deflect worms and other malware so that they never have the chance to become a problem. That kind of filtering eliminates the possibility of human error from the equation.

On the other hand, firewalls can’t catch every type of attack and, if they are determined enough, hackers will find a way to get through your firewall filter, which is why you need antivirus software. Since you need your company’s computers to actually get work done, it stands to reason that you can’t filter everything, so you just have to be as strict as you need to be with your filters while trying to provide some flexibility. It can be a thin line to try to walk.

How you use your firewall is up to you. Some companies claim that a good place to start is to block everything and then unblock sites as you go, slowly making a list of websites that will help your employees accomplish their jobs efficiently. Other companies merely use the firewall's presets and go from there. The choice is yours, but it’s important to remember that a firewall is a great tool for fighting malware if you wield it well.

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