What’s the best Linux firewall distro?

Introduction

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You don’t have to manage a large corporate network to use a dedicated firewall. While your Linux distro may already have an impressive firewall installed as well as an equally impressive arsenal of tools to manage it, the advantages don’t extend to the other devices on your network. 

A typical network has more devices connected to the internet than the total number of computers and laptops in your average small or home office. With the onslaught of IoT, it won’t be long before your router is doling out IP addresses to your washing machine and microwave as well.

The one thing you wouldn’t want in this Jetsonian future is having to rely on your router’s limited firewall capabilities to shield your house – and everyone in it – from the malicious bits and bytes floating about on the internet.

A dedicated firewall stands between the internet and your internal network, regulating the data flowing from one to the other. Setting one up is an involved process both in terms of assembling the hardware and configuring the software. However, there are quite a few distros that help you set up a dedicated firewall with ease, and we’re going to look at the ones that have the best protective open source software and roll them into a convenient and easy to use package.

Specifically, in this roundup, we’re going to dissect and compare five different distros: IPFire, OPNsense, pfSense, Sophos UTM and Untangle NG Firewall.

How we tested

While you can test these firewall distros on a spare physical PC, it’s more convenient to take them for a spin inside a virtual machine. Create a virtual network by firing up VirtualBox and heading to File > Preferences > Network. Switch to the host-only network tab and add a new network using the screwdriver icon to assign it an IP address e.g. 192.168.56.1.

Next, create a VM for the firewall distro and make sure it had two network adaptors – the first one in bridged mode, the second one as a host-only network. After installing the distro, you can assign a different IP address such as 192.168.56.2 to the second adaptor and configure it as a DHCP server to assign an IP address range of 192.168.56.20 - 192.168.56.50. From here on out, any other VM connected to the host-only adaptor will be routed through the firewall VM, so you can experiment with it safely.