You care about your safety, so you don't casually go to dangerous areas or leave your valuables for thieves to steal. This same logic applies to the online world: you should take measures to keep yourself, your devices, and your data safe from criminals.

Firewalls can be effective in defending against online crime. But it's not a good fit for everyone. What is a firewall, do you need one, and what firewalls are available for personal use?

What is a firewall?

A firewall is a software or hardware that monitors traffic on a computer network, including your wifi and mobile broadband. Think of a firewall as a club bouncer: it checks who is going in and out, and stops them if something isn't right. This makes it harder for criminals to sneak around. Firewalls can also control traffic: if you want to block specific sites and services or restrict how much data they use, a firewall can do that.

A firewall is different from a VPN. A VPN hides your activities from online spies by encrypting your connection and sending your data via special servers. But while a VPN can stop criminals from intercepting your data, it won't stop them if they have hacked your device. In contrast, a firewall protects your data traffic. For example, if criminals hack your device and try to send data to their servers, a firewall can detect this and block it.

To extend the example, a firewall is a bouncer checking who enters and leaves, while a VPN is a disguise for your data so others can't see it.

Should I use a firewall?

Do you need a firewall? A firewall is helpful if you have serious security concerns—maybe you work with very sensitive data. But generally speaking, companies are more likely to use firewalls as they can cover multiple computers and networks.

Firewalls are more technical than other security measures. A firewall creates extra security, but you must tell the firewall which rules to follow. Most firewalls cover common services, and the good ones have friendly interfaces to help you tweak those instructions. But you can also accidentally block things, and it can be tricky to unblock them.

A firewall can provide excellent security, but it's not something you install and forget. And misconfiguring a firewall can even make you more vulnerable to cyberattacks. Using a firewall is not a reactive decision, so make sure you need one before installing it.

What personal firewalls can I use?

You can get a firewall for just about any modern device, including your PC and mobile phone. Here are the most popular and well-regarded options:

Wifi router firewall: Some modern routers include a basic firewall. Using your router's companion phone app is the best way to check if you have this feature. If available, it will let you set traffic rules for devices that access the router (this is also a convenient way to restrict some apps from using too much of your internet connection).

Windows Firewall (Windows): Windows 10 and 11 have built-in firewalls. You've likely seen messages on your Windows machine asking if you want to give network access to a game or software. These requests help the Windows Firewall decide what to block.

NetGuard (Android): NetGuard is the most popular firewall for Android devices. It has a very intuitive interface, so selecting which apps can access your wifi and mobile connections is easy. NetGuard has a basic free version and a pro version with extra features.

NextDNS (Chromebook): NextDNS is one of the new-generation firewalls that can work on multiple devices, including Chromebooks, and offers many security features beyond checking network traffic. It can be easy to set up but has advanced features that might trip novice users.

Guardian (iOs): Some people believe you don't need a firewall on Apple devices because of their built-in security features. Apple devices are very secure, but they are not hack-proof. If you need extra security, Guardian is a popular iOS device firewall with a built-in VPN. But it is pretty expensive compared to other options.

For more tips and tools to make the internet less dangerous, check out this article about educating yourself about the dangers of the internet and how you can avoid becoming a victim.