Build your own firewall in 30 minutes

Worried about intruders and hack attacks? Nik Rawlinson shows how to take charge of your network security with the free pfSense firewall

You might not think you need another firewall. The one built into Windows is working all the time in the background to protect individual computers, and many routers have their own firewalls to protect the whole network. But running your own custom firewall has several benefits: it gives you more flexibility, and better oversight of what’s going on in the background.

It’s also easier to set up than you might think. You don’t need specialist hardware, and you don’t need to pay for firewall software. The open-source pfSense firewall is free for personal use, with a graphical interface for administration and all the same features as the enterprise version (the difference is that you don’t get commercial support). You can run it in a virtual machine on any PC on your network, or install it natively on a retired PC. Note, though, that you can’t run pfSense on a Raspberry Pi, as it doesn’t support the ARM architecture.

Select the ISO image, from which your virtual machine will boot

System requirements 

The pfSense firewall installs as a complete operating system based on FreeBSD, so it has the same system requirements. This means you’ll need to allocate it least 512MB of memory, and have a 64-bit processor running at more than 500MHz. If you want to support gigabit Ethernet or faster connections, it’s recommended to use a system with multiple cores running at speeds in excess of 2GHz.