In the 1990s, Microsoft had a problem: Windows seemed to suffer from endless security problems that hackers and other online villains were quick to exploit. One way to fight back was to install a firewall - an app that blocked malicious and/or unwanted network traffic and that could ensure that dodgy software couldn't sneak onto your PC.
Microsoft began building its own firewall into Windows and that's still the case today, but attacks still happen and additional software can make your system even more secure. These are the firewall apps we think you should consider using no matter which version of Windows you're running.
Some antivirus providers bundle a firewall with their free antivirus software, while others only include one with their premium security suites. Here we’re looking at firewalls that can be used alongside your regular antivirus software.
1. ZoneAlarm Free Firewall
A free firewall with real-time protection and extra tools for Wi-Fi connections
For many of us, ZoneAlarm Free Firewall was the app that introduced us to firewalls in the first place, and it was a must-have app in the days when Windows effectively told the internet "Hack me! I'm easy!"
The current version of ZoneAlarm Free Firewall hides open ports, identifies potentially dodgy traffic, disables malicious programs and connects to DefenseNet, which provides real-time security updates as new threats are detected. It also protects your computer on public Wi-Fi networks.
The only downside is that it doesn't play nice with anti-malware software other than Windows Defender, and warns of potential stability and performance problems if you don't uninstall other anti-malware software. If that isn't an issue for you, ZoneAlarm Free Firewall is the best free firewall you can download.
Download here: ZoneAlarm Free Firewall
2. Comodo Free Firewall
Effective but noisy, with easy sandboxing to stop malware in its tracks
It’s worth taking your time when installing Comodo Free Firewall because it comes bundled with an extra browser, and if you click through too hastily you might find that it's installed itself without you realizing.
Comodo Free Firewall sits in a small window at the top right of your desktop, providing one-click access to sandboxed versions of Chrome, Firefox and Comodo Browser for safer surfing. You can also run any other programs in a sandbox – ideal if you enjoy experimenting with free software.
It’s easy to control permissions for different networks, and you can create rules for specific programs too (allowing incoming traffic, outgoing traffic, both, or neither). Viruscope monitors the behavior of processes for anything that looks suspicious (though your regular antivirus software probably has this covered), and website filtering enables you to block certain sites.
Download here: Comodo Free Firewall
A free firewall designed specifically for regular filesharers
Many free firewalls use multiple forms of protection, but PeerBlock is designed to protect just one kind of problem: traffic from IP addresses that you don't trust. That narrow focus means this free firewall does its one job very well without requiring much in the way of system resources or intervention from you.
When you install it, PeerBlock asks you to choose the kind of websites you want the free firewall to block – such as adware networks, spyware, known villains and organizations such as anti-P2P groups. The free firewall automatically updates its block lists every day to keep those IP addresses away from your PC.
Download here: PeerBlock
A neat little app that gives you extra control of Windows' own firewall
TinyWall is better known for what it doesn't do than what it does: unlike some free firewalls it doesn't interrupt you with pop-up warnings about what seems to be every second bit of data.
TinyWall is designed to improve Windows' own firewall features without requiring any expert knowledge, and while it offers the same whitelisting features as other packages - to ensure that the apps you use can get online without any difficulty - it does it through hotkeys or lists rather than pop-ups.
TinyWall only takes up about 1MB on your hard drive, and is a very useful addition if you decide to stick with Windows' built-in security tool.
Download here: TinyWall
Customizable filters to protect your most personal data at router level
OpenDNS isn't a downloadable free firewall; it's a change you can make to your router's settings so it connects to the internet via OpenDNS's servers. That means the protection applies to any device on your network, which is useful in today's hyper-connected homes and businesses.
OpenDNS Home automatically blocks known offenders and offers a range of content filtering options to keep the kids away from filth too. The service is free, and there are full setup instructions for every kind of device.
Try it online: OpenDNS