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8 Best Open Source Firewall to Protect Your Network

Invicti Web Application Security Scanner – the only solution that delivers automatic verification of vulnerabilities with Proof-Based Scanning™.

Data breach statistics show millions of data get stolen or lost every day.


How secure is your network?

Do you use any firewall to protect your network infrastructure?

Earlier, I wrote about a cloud-managed firewall and received feedback to write about a FREE or open-source firewall.

So here you go.

The following free firewall is different than a web application firewall. They are to protect infrastructure instead of code or application.


An open-source security solution with a custom kernel based on FreeBSD OS. pfSense is one of the leading network firewalls with a commercial level of features.

pfSense is available as a hardware device, virtual appliance, and downloadable binary (community edition).


What you get in FREE is community edition.

I like their extensive documentation, well explained, and easy to follow. On a high-level, some of the worth mentioning pfSense features are:

  • Firewall – IP/port filtering, limiting connections, layer two capable, scrubbing
  • State table – by default all rules are stateful, multiple configurations available for state handling,
  • Server load balancing – inbuilt LB to distribute the load between multiple backend servers
  • NAT (Network address translation) – port forwarding, reflection
  • HA (High-availability) – failover to secondary if primary fail
  • Multi-WAN (wide area network) – use more than one internet connection.
  • VPN (a virtual private network) – support IPsec and OpenVPN
  • Reporting – Keep historical resources utilization information
  • Monitoring – real-time monitoring
  • Dynamic DNS – multiple DNS clients are included
  • DHCP & Relay ready

More than some of the commercial firewall features you get in FREE.

Amazing, isn’t it?

Not only that, but you also have an option to install packages with just one click.


  • Security – a stunner, snort, tinc, nmap, arpwatch
  • Monitoring – iftop, ntopng, softflowd, urlsnarf, darkstat, mailreport
  • Networking – netio, nut, Avahi
  • Routing – frr, olsrd, routed, OpenBGPD
  • Services – iperf, widentd, syslog-ng, bind, acme, imspector, git, dns-server

pfSense looks promising and worth giving a try. Check out Kamatera if looking for pfSense hosting.


IPFire is built on top of Netfilter and trusted by thousands of companies worldwide.


IPFire can be used as a firewall, proxy server, or VPN gateway – all depends on how you configure it. It got great customization flexibility.

IDS (intrusion detection system) is inbuilt, so attacks are detected and prevented from day one. And with the help of Guardian (optional add-on), you can implement automatic prevention.

You can get it started with IPFire in less than 30 minutes.


OPNSense is a fork of pfSense and m0n0wall. GUI is available in multiple languages like French, Chinese, Japanese, Italian, Russian, etc.


OPNSense got many enterprise levels of security and firewall features like IPSec, VPN, 2FA, QoS, IDPS, Netflow, Proxy, Webfilter, etc.

It is compatible with 32bit or 64bit system architecture and available to download as ISO image and USB installer.

NG Firewall

NG Firewall by untangle is a single platform where you can get everything you need to protect your organization network.


It has got a beautiful dashboard, which you can check in the demo in the video below.

YouTube video

It works like an app store where you can enable or disable a particular app (module) based on the requirement.

In the FREE version, you get NG Firewall platform, free apps, and 14 days trial of paid features.


Smoothwall Express is a free solution with a simple web interface to configure, manage the firewall.


Smoothwall express supports LAN, DMZ, Internal, External network firewalling, web proxy for acceleration, traffic stats, etc.

Shutting down or rebooting is possible directly through the web interface.

Note: The following two programs are specific for Linux servers.


ufw (uncomplicated firewall) works with Ubuntu. It provides a command-line interface to manage the Linux kernel packet filtering system (netfilter).


csf (ConfigServer security) is supported and tested on the following OS and virtual servers.

  • RHEL/CentOS
  • CloudLinux
  • Fedora
  • OpenSUSE
  • Debian
  • Ubuntu
  • Slackware
  • OpenVZ
  • KVM
  • VirtualBox
  • XEN
  • VMware
  • Virtuozzo
  • UML

csf is a stateful firewall, login detection, and security solution for Linux servers.


Endian Firewall Community (EFW) is a powerful, easy to install and use Linux based security product for home and small networks. It can transform a bare-metal hardware appliance into a powerful and effective unified threat prevention and management solution comprising of a firewall, an antivirus, VPN, and content filtering capabilities in a single box.

The stateful firewall allows you to protect your network from a wide range of attacks and threats in addition to offering a well-protected VPN to secure the environment for your remote employees.

endian firewall community

EFW key features include;

  • Provides real-time monitoring, logging, and reporting of the network activities, resource usage such as bandwidth, etc.
  • Enhancing secure remote access through the Endian community VPN
  • Enhanced event management.
  • Improved security for network web and email services in addition to an intrusion prevention system (IPS).


I hope above listed free solution for firewall helps you to save money and protect your infrastructure from being hacked.

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