The Best Free Firewall Software – August 2017

Posted by Jamie on July 31, 2017

The same as you wouldn’t leave home for work without locking your door or park your car without locking it, you shouldn’t every use a device on the internet without securing that too. Firewall software is one way to do that. Here are what I think are the best free firewall software to keep you safe in 2017.

A firewall is not a get out of jail free card that guarantees your safety while online. It will help protect you because it forms part of defense in depth that helps keep you safe. Along with a router-based hardware firewall, good internet habits, a decent antivirus and malware scanner, a firewall will help keep you safe while online.

Firewall software comes in both free and paid-for forms. While company marketing may make you think otherwise, the level of protection offered by both is exactly the same. Where free and paid-for firewalls differ is in the features the package includes. Free firewalls will just include a firewall and not a lot else. A paid-for firewall may offer extra features, premium support and other bells and whistles. The actual protection will be the same.

Companies want to make money but also recognize that they have a responsibility to help keep the internet safe. Hence the free products. The same goes for antivirus and malware scanners. If they provide top class free products, if you ever want to upgrade your experience, you will likely choose the vendor of the free product you use. That is where they make their money from free products.

The best free firewall software 2017

This guide concentrates on Windows computers. Mac is inherently more secure and suffers less from malware than Windows. As long as you have enabled the default firewall in Mac OS, you have enough protection already. Windows does come with a built in firewall but it does not currently monitor outgoing traffic which is a big security flaw. That’s why the third-party firewall market is so buoyant.

So what are the best free firewalls available right now?

Comodo Firewall

Comodo Firewall is my firewall of choice. I have it installed on all of my computers and on my phone. It provides a good level of protection, doesn’t get in the way, offers HIPS protection, sandboxing, a game mode and configurable rules. For a free firewall, there is a lot of utility in this program.

The installer may be quite large but the program itself is light on resources. Make sure to opt out of the browser and search engine change when installing though. Comodo runs a widget in the top right of your screen. You can turn this off in Settings if you wish.

Zone Alarm Free Firewall

Zone Alarm Free Firewall used to be my firewall of choice until the newer version of Comodo came out. Zone Alarm is light, easy to use and fully featured. It is one of the most popular Windows firewalls around and offers a good level of protection at no cost.

Zone Alarm has an added benefit of a live connection to DefenseNet. This is a live database of real-time threats that can alert your firewall to emerging attacks. If you use the internet a lot, or use public Wi-Fi, this is a great feature.

Emsisoft Internet Security

Emsisoft Internet Security is another free firewall program that offers credible protection at no cost. Less well known than Comodo or Zone Alarm but no less proficient, this program used to be known as Online Armor before being changed. The program is light on resources and offers inbound and outbound traffic monitoring.

The UI is simple and uncluttered, there are varying levels of protection depending on how paranoid you are or how much you use the internet. Reviews of Emsisoft Internet Security seem very positive too. This is the only firewall I haven’t used so you will have to try it yourself to see how it works.


At first glance, Privatefirewall looks like something out of the 1990s. The website is very low tech and the interface of the program itself isn’t much better. However, once you get past that, the program is very good indeed. It has some good features, high levels of protection and a simple traffic blocking command for all internet traffic.

Ease of use is at the heart of this free firewall program and once installed, you will quickly begin bending it to your will and blocking programs. Despite first impressions, Privatefirewall is a very competent program and one I have used extensively.


TinyWall is my final recommendation for free firewall software to keep you safe. It is a little different than the others in that it isn’t actually a firewall at all. TinyWall is a hardener for Windows Firewall. That means it is designed to make the built-in firewall more usable, more controllable and more powerful.

I have used TinyWall a lot and if you already have a firewall on your router, is a good option for an extra layer of protection. It still doesn’t monitor outgoing connections but strengthens the default protections within Windows Firewall to credible levels.

Why not use Windows Firewall?

The argument about the quality and protection offered by Windows Firewall rages on and will likely do so for many years to come. While it has been steadily improved over the years and now offers good levels of inbound protection, it still doesn’t do anything with outbound traffic.

By default, Windows Firewall allows all outbound traffic unless you have created a rule to control it. That means any malware or Trojan that has found its way onto your computers has free rein to communicate with its host server and send it all your details. It is for this reason that I would never advocate depending entirely on Windows Firewall even though the levels of inbound protection are now good.

How does a firewall work

After reading this far, you now know why you need a firewall and what firewalls to consider. If you would now like to learn how a firewall works, read on.

Firewalls in society are structures that stand between people and fire. Think fireproof walls between your house and garage. Think those wide spaces of cleared land between stretches of forest or even the bulkhead between your car’s engine and the cabin. All are designed to protect humans from risk by creating a gap or impenetrable barrier. A computer firewall does much the same thing.

There are two types of computer firewall, software and hardware. We have discussed software firewalls already. They are programs installed onto any device that accesses the internet. A hardware firewall is either a dedicated device that sits on a network or a router feature that has firewall capabilities. Many consumer routers have this ability that acts as the first or last layer of defense for your network. The main difference between software firewalls and hardware firewalls is the latter usually works independently of the device. It has its own hardware resources and will only be attached to a computer via the network.

They have a downside too, like Windows Firewall, a hardware firewall usually only monitors inbound traffic unless you configure it otherwise.

Both types of firewall work by filtering web traffic. They use three methods of doing this, packet filtering (stateless), stateful and application layer filtering.

Packet filtering firewall

A packet filtering firewall will inspect all traffic flowing through it and will allow or deny that traffic depending on what the packet header contains. Packet filtering firewalls are called stateless firewalls because they do not know what is sending the traffic. Some will allow users to set rules to further refine the level of freedom or protection the firewall offers.

Stateful firewalls

Stateful firewalls record all connections and watch them as they progress. That way they know whether a particular program has a legitimate connection to the internet, whether it should be transmitting traffic, what kind of traffic and whether all that matches to the current state of that program. Stateful firewalls are complicated but very good at what they do.

Application layer filtering

Application layer filtering firewalls adds to the stateful feature by also analyzing the data being transmitted. It matches the program with the application and checks its rules to see whether that connection is allowed or not. It then sends or drops traffic according to those rules.

There are other types of firewall such as circuit-level gateways and multilayer inspection firewalls but these are enterprise-level. Not really relevant to home users.

Most free firewall software uses packet filtering. This is a good level of protection for small networks or home users. It does not allow forensic investigation or content filtering but combined with a hardware firewall within a router, offers plenty enough protection for most uses.

Considering the importance of a firewall, the list of the best free firewall software to keep you safe in 2017 is quite short. It is fortunate that quality outweighs quantity!

Got any other suggestions for good quality free firewall software for home users? Tell us about them below if you do!

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