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 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 2 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 (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, you also have an option to install packages with just one click.


  • Security – 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. Read more about features here.


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 got the beautiful dashboard, experience the demo here. 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.

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