Firewall basics part 1: why we need firewalls?

In an earlier article (see Free essential software for Windows), I recommended the use of firewalls, among other software, for protecting your PC. However, I didn’t present any reason why we need firewalls in that article. This article expounds on the need for firewalls, the differences between hardware- and software-based firewalls, and how to troubleshoot your firewall in case you find yourself having problems with your PCs after installation.

Why do we need to have a firewall?

When we go on the Internet, we put the possibly sensitive data residing on our PCs at risk from attack by hackers intent on getting that data for any reason, including possible use in criminal activities. If your system has been penetrated, you might get a call one day from law enforcement asking you to explain why you’ve been attempting to break into their websites (I agree that this is a bit extreme, but it may happen). Having a firewall alleviates that risk, potentially saving your reputation in the process. Moreover, your PC itself gets protected from unauthorized use. You don’t want a hacker to borrow it while going about with whatever nefarious activity they’re engaged in at the moment, do you? The above is the most simplistic way I can think of to explain why we need firewalls, without going to technical details that might bore the rest of us.

Now, we go to the differences between hardware- and software-based firewalls.

A hardware-based firewall is typically found in the router you used to connect the different PCs on your home network. There are dedicated firewall appliances, as hardware-based firewalls are typically called, but these are typically more expensive than your router. A software-based firewall, on the other hand, is a computer program you install on your PC. When choosing a firewall for your network, the primary consideration would eventually be ease of installation and pricing.

Software-based firewalls are easier to install and cheaper, and are recommended if you only have one PC. However, their primary disadvantage is that they can’t stop an attack through a security hole in your Windows operating system. For those, you have to apply patches from Microsoft. Once patched, your software firewall will be reliable again. A hardware-based firewall can stop this type of attack as it sits between your Internet connection and your PC or network, effectively blocking the attack before it reaches your PC.

Firewalls can potentially wreak havoc on your home network. After installing a firewall, you might find that you can’t run services or programs that you’ve had no trouble running before. To ensure that this won’t happen to you, you need to know how to properly configure your firewall. This is a little difficult to explain here, considering that both hardware- and software-based firewalls have their pecularities, depending on the brand. However, when you encounter problems with programs or services after firewall installation, you may want to check the following:

• By default, most firewalls block all traffic coming from the Internet. This is good. But if you want to allow users to access your network, you need to create a rule allowing such access, e.g. create a rule that would allow other users to connect to the FTP server on your PC.
• If you’re having problems running a program that connects to the Internet through your firewall, try setting it up on the firewall’s demilitarized zone, or DMZ, which is a portion of your network that’s accessible to and from the Internet, but is distinct from your private network.

That about covers it all. I’ll devote more time to firewalls in subsequent articles.

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