Best free firewall software
The need for computer firewalls developed as internet technology spread and the development of malware increased.
Trojans could open up ports on user PCs to secretly send data, and sniffers could look for vulnerabilities in your network connection that would allow it to be exploited.
Even though developments in anti-virus and malware technology have improved significantly over that time, firewalls still remain a recommended requirement for all PC users because the risks have evolved rather than stopped.
While any good anti-virus program can prevent obviously malicious activity on your PC, sometimes software and apps can abuse their permissions to create unauthorized network connections, which could be exploited to collect user data from your computer.
This is where firewalls really come into their own, insisting that the software on your PC has your express permission to connect online, while also keeping remote attacks blocked.
Here we showcase the best in firewall protection for your computer.
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Offers real-time protection and extra tools for Wi-Fi security
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 back 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, and offers 5GB of online data backup via IDrive.
When you're installing the software, read through each step carefully if you don't want to set Yahoo as your default homepage; the 'Customize installation' option is quite well hidden. You'll also need to submit an email address to activate the firewall, though ZoneAlarm promises not to share it with any third parties. If that isn't an issue for you, ZoneAlarm Free Firewall is the best free firewall you can download.
An effective solution 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, as these apps can sometimes offer more than you bargained for.
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.
Comodo Free Firewall will also offer to set Yahoo as your homepage, but the checkbox is much easier to see and untick than ZoneAlarm's. It will also suggest making its own secure Comodo Dragon your default browser and importing your settings from Chrome. You can't opt out of installing the browser, but you can choose not to use it.
Comodo Free Firewall will offer to change your DNS (domain name resolution service) provider to Comodo Secure DNS for more faster, safer browsing.
A well-designed, information-packed firewall to boost your security
GlassWire is a slick looking free firewall that shows you exactly which programs are sending and receiving data over your network, and how much, making it easy to identify anything unusual. There's a huge amount of information available, which might seem alarming at first, but you can clear all of GlassWire's logs in a few seconds.
You'll be notified when a new application or service wants internet access, and you can allow or block it with a single click. In actual fact, GlassWire is really just an interface built on top of the Windows firewall, so while certainly more attractive (and informative) than the latter, it’s not going to be any more robust.
The premium versions of GlassWire includes some extra features like monitoring of your webcam and microphone, storing records for more than a month, and monitoring multiple remote connections, but for basic use the free edition is superb.
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 (now on version 2.1) 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 lives up to the ‘tiny’ part of its name, and only takes up about 1MB on your hard drive. It is certainly a very useful addition if you decide to stick with Windows' built-in security tool.
Customizable filters to protect your personal data at a 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' 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, and it helps prevent phishing attacks. The service is free, and there are full setup instructions for every kind of device.
For more info on this solution and other alternatives, check out our guide to the best free and public DNS servers of 2019.
Privatefirewall offers something of a hand-on experience for users who want to control every part of their firewall software. Installation requires a walkthrough as it's not automatic, and you're expected to set up your own configurations, though guidance is provided.
The software has multiple parts to support the firewall process, not least an application manager and a process monitor. You can also track port use and traffic, and filter according to whichever rules you set up. There's also the ability to set up a whitelist of IP addresses, which can be useful for remote networking, and untrusted IPs and websites can be blacklisted.
The ability to customized so much of the firewall is what makes Privatefirewall especially notable. The only issue for many users might be that the limited GUI and text-heavy process, along with the range of options and settings available, could make Privatefirewall somewhat intimidating.
However, if you can get past that state, then Privatefirewall is a simple but powerful program that allows full hands-on control of your firewall security - just so long as you don't mind getting your hands a little dirty in setting it up.
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