Top 10 Open-Source Firewalls

Published on
06/09/2021 11:09 AM

In today’s digital world, there are countless spammers, hackers, and criminals looking for ways to pry into our online lives and gain access to secure information. As things like remote and hybrid work become more common, companies need to ensure they’re investing in the latest security technology. This includes exploring everything from VPNs to open-source firewalls. 

An open-source firewall is a solution designed to act as a guard between external and internal networks. In an open-source environment, you download a firewall created and maintained by a community in an ever-changing environment.

Today, we’re going to examine some of the top open-source firewalls for companies to consider in the new, digital world.


Widely regarded as the world’s most trustworthy open-source firewall, PfSense is a free-to-use solution for securing your business. Thousands of enterprises rely on this software to securely connect to the cloud and keep business data under wraps. The PfSense environment builds on the concept of stateful packet filtering, with a wide range of features you would generally only find in other, more expensive firewalls. 

With PfSense, companies can access a comprehensive network of security solutions for all kinds of environments. The platforms this company uses are among the most reliable in the world, engineered to deliver the best level of confidence, security, stability, and performance. PfSense also offers plenty of support in the form of documentation too.


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The OPNSense firewall is easy-to-use, free, and ideal for infinite scalability. This open-source project promises best-in-class virtual private networking, intrusion detection, and a powerful firewall with support for both IPv6 and IPv4 live view on passed and blocked traffic. Multi-WAN capability is included with hardware failover, state synchronization, and intrusion detection. 

Two-factor authentication is available throughout the system, both for the user and services like VPN. Multi-language support is available for all kinds of customers, along with an intuitive user interface for easy access and development.


Known for offering a host of security solutions to today’s digital brands, Untangle’s advanced open-source firewall delivers a powerful environment for enterprise networks. You can install the firewall on a dedicated appliance, a server, a virtual machine, or even in the public cloud, and use it to keep your entire company safe. 

Because Untangle firewall software is available as a free download in multiple formats, it can suit all kinds of deployment needs. You can download a USB image, ISO image, or VMware image, and the company offers the same software package as standalone hardware, which you can connect to your existing network.


A Linux-based firewall intended to offer advanced network security for businesses, IPFire provides extensive protection from attacks through DDoS and internet connections. The software comes from a dedicated online community featuring thousands of developers. Aside from being powerful, IPFire’s software is also lightweight and easy-to-implement. You even get access to an Intrusion Detection System for analysing your network traffic and pinpointing potential exploits.

If attacks are detected within IPFire, you’ll be able to set the system up to automatically block the attacker. Like many leading firewalls, IPFire comes with a web-based management interface for setting changes. You can also configure the network to suit different needs, like advanced graphical and logging reports.


The Endian Firewall Community, or EFW, is an open-source UTM and Firewall solution offering a unique combination of capabilities. The software is available to access for free, although you’ll need to handle it yourself, as there’s no support available from the developers. With this software, companies can quickly establish web and email security with powerful analytics.

When you download EFW, you don’t just get a turnkey Linux firewall solution; you also get unified threat management and an open-source anti-virus protection system. You can even unlock extra support in the form of powerful VPN services.


Available on its own or as part of a package, Smoothwall’s open-source firewall provides 7 layers of application control. The Smoothwall firewall combined with Smoothwall filter offers companies a complete package for online protection. Alternatively, you can access the firewall on its own for bandwidth management, gateway anti-malware protection, and a real-time dynamic threat filter.

Focused on the UK education environment, the Smoothwall firewall is one of the most exciting tools on the market, with thousands of forum members contributing to the Linux and GNU-based solution at all times. The OS is even security-hardened to reduce the risk of firewall vulnerabilities for users. For those in need of extra help, UK support is available.


Intended for those with a basic knowledge of coding, the CSF firewall solution, otherwise known as ConfigServer Security and Firewall, is a comprehensive tool for online protection. The Stateful Packet Inspection firewall was built for use with Linux servers, with access also available for things like Ubuntu, VirtualBox, VMWare, and many others. 

For those keen to access the latest technology in firewall protection, CSF is constantly improving with a huge community of developers working on keeping the script as secure and innovative as possible. You can even get real-time insights into your firewall and how well it’s performing.

IPCop Firewall

Another Linux-based solution for open-source firewall protection, IPCop is a well-known solution for online security, designed to help secure businesses and home networks alike. Because there’s no graphical interface, you’ll need to be confident using command-line technology to use this service – which may make it less accessible for some users.

Though this software does demand some technical knowledge of firewalls and servers, it also provides a lightweight opportunity to enhance security for more advanced users. The image size is tiny at 60MB, and it’s suitable for a range of systems. Unfortunately, the last version of the product was released in 2019.


A Linux-based open-source and new-generation firewall solution, Shorewall has a range of fantastic features to offer, including a Net filter system for tracking and monitoring potential threats. Shorewall allows for network partitioning and role-based access management. There’s support for multiple systems, a high number of network interfaces, and complete customization for modifying the firewall according to your requirements.

Blacklisting is available for IPs, and companies can access features for mapping and traffic accounting, with tools for ease of virtualisation also built-in.


The VyOS Open-source firewall network operates on the GNU/Linux environment, with a unified management interface for all functions. The solution comes with access to a free routing platform that competes directly with other commercially available solutions from leading network partners. The VyOS solution also runs on standard systems, so it’s suitable for use as a router and firewall platform for all kinds of cloud deployments. 

With VyOS, companies can access a comprehensive firewall system with access to industry routing protocols, multi-path and policy-based routing, and more. You can even set up the OS system on your specific VPN solutions for remote workers.