What is a Personal Firewall? (Simplified)

Firewalls are a security measure that has been in place for many years. They help protect your computer from outside attacks by blocking access to the internet or other computers on your network. However, they can also be used to restrict what you do with your computer. 

That is where personal firewalls come into play! Personal firewalls are installed on individual computers and monitor all activity coming in and out of it. When an application tries to communicate with the outside world, the firewall blocks it until it is authorized by you! You can set rules about who gets access or when they get access, so that only people that need information will have them while keeping others out!

What is a Personal Firewall?

A personal firewall is software that monitors and protects your computer from unwanted access. It can prevent unauthorized users (hackers, viruses, etc.) from accessing the system via the Internet. They work like a virtual wall between you and other people on the web to stop them from using your data or devices for nefarious purposes.

The best way to describe it is as an “electronic bouncer” — when someone tries to get in but isn’t allowed, they are sent straight back out again! A good analogy would be entering into a crowded party with many different people trying to come through at once. The bouncers filter all of this traffic so only those who have been invited can enter while keeping anyone else outside where they can’t do any harm.

Sometimes, however, the bouncers get it wrong and they don’t let someone in who is allowed to be there. A firewall would not stop this from happening if an error was made by one of the many people at the party responsible for checking guests’ identities. It’s also important to remember that a firewall’s job is not 100% effective — some hackers are very good at what they do.

Nevertheless, using a personal firewall will protect you against most risks on your computer network while allowing you full access to all its features without worry or fear of compromising security; which ultimately leaves you free to surf online with peace of mind about your privacy and security.

How Does a Personal Firewall Work?

A personal firewall monitors all incoming and outgoing data on your computer. When an application tries to communicate with the outside world, the firewall blocks it until it is authorized by you. You can set rules about who gets access or when they get access, so that only people that need information will have them while keeping others out.

Personal firewalls can be configured to allow or block individual connections based on the application making them, where they are going and how often they do so. For example, you might configure your firewall to block web browsing but allow email access to a particular website at home during work hours only (or vice versa).

You’re probably wondering what kind of tasks a firewall carries out. Here are just some examples:

  • Monitor communication between applications running on your PC;
  • Create logs every time an external application attempts to connect to another program inside or outside of your network;
  • Allow/block certain programs from communicating over networks like LANs (private), WANs (Internet) etc.;
  • Allow/block certain applications from accessing the Internet.

How is a Personal Firewall able to do all of this?

A firewall works by using either static rules (programmed manually) or dynamic rules, which are configured automatically based on the traffic they see. If your computer receives unexpected communications from an application you haven’t installed yourself, it could be because a virus has infected that application — and now the firewall knows about it! It can then be configured to block any future communication between those applications until such time as you tell it not to. Essentially the firewall will learn what’s bad for your PC as well as what isn’t and adapt its behavior accordingly. This way if anything changes in how data enters or leaves your machine, the firewall recognizes this new information and learns from it quickly so that it can always adapt to evolving challenges.

The firewall will also use its logs (see above) to tell you when it has blocked something, which applications are attempting to access the Internet and for what reason it did so. This way if one of your programs is trying to send or receive data that shouldn’t be happening at all (like sending personal details like credit card numbers across the web), then you’ll know about it before anything bad happens!

What Operating Systems do Personal Firewalls run on?

Personal firewalls come in many different forms — some even built into devices such as routers, while others need installing onto your computer system manually by yourself; usually through a specific app store or website just for them. Some examples include:

  • Windows Firewall (built in to all versions of Windows)
  • Comodo Personal Firewall (for both PC and Android devices; free for home users, paid-for options available too);
  • Norton 360 Online Family Safety (offers firewall protection only — no antivirus software included. Free service.)

Some of these may be available to use for free while others are paid-for.

What Else Can I Do With My Firewall?

Many firewalls will come bundled with additional features, some examples include:

  • Parental Controls (which you can configure the firewall’s behavior based on your children’s online activities);
  • A dedicated antivirus application that includes a firewall built into it too; or even better, an all in one security suite that provides both protection and PC optimization tools — perfect if you’re looking for more than just basic security! There are many options out there so make sure to shop around before choosing which product is best suited to your needs.

Who Needs A Personal Firewall?

Anyone with a Windows-based PC (or Mac) should consider installing some form of Personal Firewall onto their machine. If you don’t use your computer for surfing the web, sending/receiving email, or downloading apps from the Internet then you might not need one. But since most of us do these things, it’s best to have some form of protection in place just in case something bad happens down the line.

Why Do You Need A Personal Firewall?

On a final note, there are many reasons why you should have some sort of firewall installed onto your PC. Here are just three examples:

  • While browsing the web on Android smartphones and tablets with an insecure wireless connection (in cafes or at home for example), not having a Personal Firewall enabled could allow hackers to intercept all data being sent back and forth between your device(s) and websites. If someone gains access to this information they can then use it in any number of ways — including stealing sensitive details like credit card numbers! A Personal Firewall will help prevent these types of attacks by stopping unauthorized communications from happening in the first place;
  • When using open Wi-Fi networks that don’t require passwords (such as on some public transport systems, in hotels or at work), your PC could be on the receiving end of any number of attacks from other people’s devices. Public Wi-Fi is extremely insecure and should not be used for storing sensitive data — such as online banking details! Since a firewall can monitor all traffic leaving/entering your machine it will help stop this sort of activity;
  • Many programs (like games) require access to the web during their initial setup process; even if you’re just downloading extra content like updates and new levels. While using these sorts of apps it’s very easy for bad guys to take advantage by infecting them with malware that then gets installed onto your computer without permission. By having a Personal Firewall enabled you’ll be able to stop this from happening as the firewall will only allow authorized communications to take place.

Some firewall programs can also resolve many other annoyances that you might be experiencing with your computer. For example, some of them will automatically optimize your PC’s memory and disk usage to help speed up sluggish performance (especially after a software update); or even better still, they’ll clean out all those old temporary files left behind by the applications installed on the system!

Common Types Of Personal Firewalls

Windows Firewall

Microsoft’s own Personal Firewall is included with every copy of the Windows operating system and can only be used to protect your computer from malicious attacks made over a local network or through the Internet. It comes pre-installed on all PCs running any version of the Windows OS — so chances are you already have it!

Outbound Filtering Firewalls (also known as ‘Proxy Servers’)

This type of firewall will monitor all outbound traffic leaving your machine, even if sent by legit programs/apps that you’ve installed yourself. If for some reason an unauthorized communication attempt is detected then they’ll block it in real time before anything bad happens. Many commercial products have this feature while some free ones do not.

Inbound Filtering Firewalls

This type of Personal Firewall will track all inbound traffic sent to your PC and block anything that looks suspicious or doesn’t have a valid return address (or it’s coming from an unknown IP). While this can help protect you, these firewalls tend to conflict with certain programs/apps — such as online games for example; and as a result can cause problems with connectivity and performance.

Application Layer Firewalls

This is the most advanced type of firewall that you’ll find anywhere and it’s one that we strongly recommend for all users to have installed! It works by monitoring all traffic at the application level (in both directions) between your computer and everything else — such as websites, cloud storage providers like Dropbox or Google Drive; even other PCs on your network running legit software/apps. 

This sort of Personal Firewall will allow through only those communications which are authorized by you (i.e., anything originating from any PC listed under ‘Safe Domains’ in its settings). Since every single byte traveling over your machine must pass through this layer there’s no chance of a false positive triggering and it’s very efficient at blocking malware — even the sneakiest of all Trojans!

Examples of Each of Types of Personal Firewalls

  • Windows Firewall: Microsoft Windows Firewall
  • Outbound Filtering Firewalls (also known as ‘Proxy Servers’): Comodo Personal Firewall, ZoneAlarm Free Firewall, ESET Online Scanner
  • Inbound Filtering Firewalls: AVG Internet Security 2015, Avast! Antivirus Pro, Panda Cloud Cleaner
  • Application Layer Personal Firewalls: BitDefender Total Security 2012/2013/2014/2015; Kaspersky PURE / Total Security 2015.

Which Firewall Should You Choose for Your Needs?

  • Windows Firewall: Good for beginners and those who don’t want to spend money.
  • Outbound Filtering Personal Firewalls (also known as ‘Proxy Servers’): Great choice if you’re concerned about your privacy online, but can cause problems with some programs/apps.
  • Inbound Filtering Personal Firewalls: a very secure solution that should be used by everyone wanting maximum protection from threats — provided it doesn’t affect performance too much on slower PCs;
  • Application Layer Personal Firewalls: A great choice for power users who want the best possible protection from all kinds of online threats, but can get complicated to set up;

Common Misconceptions About Firewalls

A firewall isn’t just about protecting your computer from hackers on the Internet. It’s also designed to protect you against malware that may be running locally on your PC (or even other PCs on your network). It has many advanced features which will help keep all of your devices safe while surfing online, shopping at Amazon or eBay, checking email and logging into Facebook etc. 

Firewalls are not made by criminals looking for a way to steal money directly from our bank accounts either! Most of them don’t even track any personal data since they’re built with privacy in mind — unlike more mainstream software like Windows Defender or Microsoft Security Essentials which must be configured very carefully if you want maximum security without sacrificing too much performance (and yes, you can use them at the same time).


Most firewalls are Open Source too which means that they’re constantly being improved by a large community of people who have no interest in harming you or your money. If anything, these hackers WANT to keep software like theirs secure so that their families and friends aren’t put at risk if it gets into the wrong hands! 

The main reason why cyber criminals write malware is because they want us to click on links leading to shady websites — not for financial gain… And even then you’d be surprised how little cash most of these guys make through this sort of thing anyway. That’s partly due to banks doing such a good job preventing online fraud but it also has to do with how much money is tied up in ransomware and other types of malware.

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