10 Best Open Source Firewalls | Open Source Firewalls

10 Best Open Source Firewalls | Open Source Firewalls

‌‌Today, as all our data is on phones, laptops, and PCs, the chances of cyber theft increase on a large scale. And, when you have a medium that can protect your private data, why wouldn't you prefer it? That's what the firewall works for. It protects your system from any kind of malicious attacks and protects your private data.

‌‌So basically, a Firewall is network security software that checks the ongoing and outgoing network traffic and further allows or obstructs data based on various safety rules.

The firewall makes sure that there must be a blockage between the internal network and incoming traffic from any outside sources, mainly to restrict malicious traffic.

‌‌Corporate companies mainly prefer three fundamental types of firewalls to protect their data and devices, which are: stateful inspection, packet filter, and proxy server firewalls. Speaking of which, today in this article, we are talking about the best open source firewall that would work amazingly for your company. So, let's get started!

Perimeter 81
Untangle Firewall
CSF Firewall

Perimeter 81

Perimeter 81 - Best Open Source Firewall
Perimeter 81 - Best Open Source Firewall

‌‌When it comes to the best open source firewall, Perimeter 81 never missed the list. It is FWaaaS (Perimeter 81's Firewall as a Service) is quite simple to configure and facilitates secured access for the cloud-based resources which are arriving from outside of the office.

Plus, it gives access to admin for certain network sources based on the group and user identity. Which gives the ultimate control to the administrators to decide who can access which resource.

‌‌What makes Perimeter 81 different from others is that it gets instantly deployed in the cloud. And all the granular permission-bassed policies and user segmentation make the functioning of FWaaS pretty effective.

‌‌Perimeter 81: Features

  • Cloud agnostic integration
  • Simple configure & maintain
  • Secure remote access
  • Granular permission-based policies
  • Centralized management

Untangle Firewall

Untangle Firewall - Best Open Source Firewall
Untangle Firewall - Best Open Source Firewall

Another amazing open-source firewall is Untangle Firewall, which is based on Debian 8.4. Untangle is now a part of Arista Networks. It is very easy to install on any hardware or digital machine. The basic level network function in Untangle Firewall is enabled through free and paid applications that add more functions and functionalities which are managed on a web-based user interface.

Also, it has an NG Firewall that you can purchase, whereas Untangle Firewall comes pre-installed.

‌‌Untangle Firewall: Features

  • Virus blocker
  • Spam blocker lite
  • Phishing blocker
  • Intrusion prevention
  • OpenVPN
  • Web Monitor
  • Restricted portal

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OPNsense - Best Open Source Firewall
OPNsense - Best Open Source Firewall

Being a complete open source firewall, OPNsense is based on FreeBSD along with strong overpowered software developed by Deciso.

Earlier, when m0n0wall failed in February of 2015, OPNsense Firewall was built as an alternative by Manuel Kasper and the whole developers' attention shifted towards it.

This OPNsense Firewall carries a web-based user interface that is used on both i386 as well as x86-64 platforms.

‌‌OPNsense: Features

  • Capital portal
  • Virtual private network
  • Forward proxy caching
  • Hardware failover and high availability
  • Built-in reporting
  • Intrusion exposure and inline prevention
  • DHCP server and delay.


pfSense - Best Open Source Firewall
pfSense - Best Open Source Firewall

Built with FreeBSD OS, pfSense is an open-source security platform that comes with a custom kernel. This firewall is counted among the leading networks integrated with commercial levels of features.

It is in-built with LB to distribute the loads among the various backend servers.

‌‌Moreover, pfSense comes in different choices, such as hardware devices, downloadable binary, and digital apps. And their extensive documentation feature is appreciated enormously.

‌‌pfSense: Features

  • Server load balancing
  • Network address translation
  • High-availability
  • Real-time monitoring
  • Limited connections
  • IP/port filtering
  • Dynamic DNS


Endian - Best Open Source Firewall
Endian - Best Open Source Firewall

Being a turnkey Linux security dispersion, Endian Firewall Community is quite promising with its services and features. It enables full-proof security to any unsecured device and turns it into unified threat management.

Among the various open source firewalls, Endian is considered the most precise security software which is very easy to install, design and function. Endian is amazing when it comes to monitoring network traffic, preventing hacking, preventing any virus attack, and providing complete privacy.

‌‌Endian: Features

  • Stateful Firewall
  • Quality of Service (QoS)
  • Multi-WAN
  • Antivirus


IPFire - Best Open Source Firewall
IPFire - Best Open Source Firewall

IPFire is a Linux-based firewall that provides an advanced level of network security for corporate companies. It provides extensive protection and avoids any attack through DDoS and the internet.

Along with such a high-protection level, IPFire is quite lightweight and easy to install. Through this software, you can get access to an intrusive detection system to analyze your network traffic and highlight the suspected exploits.

‌‌IPFire: Features

  • Web-based management interface
  • Web proxy
  • Intrusion detection
  • VPN
  • Virus scanner

CSF Firewall

CSF Firewall - Best Open Source Firewall
CSF Firewall - Best Open Source Firewall

CSF Firewall software was developed for those who have some basic knowledge of coding. Also known as ConfigServer Security and Firewall is an advanced comprehensive tool to protect private data from any online threat. It was mainly built to use the Linux server and also has access to VirtualBox, Ubuntu, and many more.

‌‌CSF is known for being integrated with the latest technology which keeps on improving with every update by the huge community of developers. The main intent here is to provide an absolutely secure service.

‌‌CFS: Features

  • Login Authentication Failures
  • Messenger Service
  • Port Flood Protection
  • Stateful Packet inspection


Shorewall - Best Open Source Firewall
Shorewall - Best Open Source Firewall

With a great range of features, Shorewall is a Linux-based open-source firewall software integrated with the latest technologies. It comes with an amazing feature range that includes a Net filter system, monitoring potential threats, and many more.

‌‌Shorewall is widely appreciated for its network partitioning and role-based access management. It is available for several systems. It gives the customers the freedom to customize the firewall based on their requirements.

‌‌Shorewall: Features

  • Masquerading/SNAT
  • Port Forwarding (DNAT)
  • One-to-one NAT
  • Proxy ARP
  • Multiple ISP support
  • Net Filter System
  • Monitoring potential threats
  • Mapping and traffic accounting


VyOS - Best Open Source Firewall
VyOS - Best Open Source Firewall

‌‌Being an open-source firewall software, VyOS runs on a GNU or Linux environment along with a unified management interface. It provides free access to routing platforms that are competitors in the Industry with commercial-level features.

Moreover, VyOS runs smoothly on standard systems which makes it easy to use as a firewall as well as a router for managing all kinds of cloud deployment.  With this, corporate companies get access to a comprehensive firewall system that comes with multi-path, industry routing protocols, and policy-based routing.

‌‌VyOS: Features

  • SFlow and NetFlow
  • Quality of Service policies
  • Dynamic and static routing
  • Tunnel interface
  • IPv6 and IPv4 traffic firewall rulesets
  • Network address translation


ClearOS - Best Open Source Firewall
ClearOS - Best Open Source Firewall

Based on CentOS, ClearOS is an open-source firewall that is developed to recast the standard level of a PC and turn it into an accurate internet server with the firewall solution in it.

Mainly, for corporate companies, ClearOS has three editions which are ClearOS business, ClearOS community, and ClearOS home.

‌‌ClearOS community edition is the free version of this firewall software while the business and home editions need to be purchased first for the subscription.

Moreover, ClearOS has a complete network firewall function whose features can be enhanced by adding different applications such as DMZ, DHCP server, DNS server, and many more.

‌‌ClearOS: Features

  • Stateful firewall
  • Intrusion detection and prevention system (SNORT)
  • Virtual private networking
  • Web proxy
  • Content filtering
  • Antivirus (Squid, DansGuardian)
  • E-mail services

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In conclusion, we can say that there are multiple open-source firewall solutions available in the market. With pfSense, perimeter 81, Untangle, ClearOS, and all the above-mentioned firewalls are proven to be best with their services and features. These are competitors in the industry and work on providing accurate service to corporate companies. Everyone needs to protect their private data, especially corporate companies. And the best way to do so is by installing a firewall.


What is a Firewall?

It is network security software that checks the ongoing and outgoing network traffic and further allows or obstructs data based on various safety rules.

What is Cyber Security?

Defending electronic systems, servers, websites, phones, and computers against online malicious attacks is called Cyber Security.

What is Cyber theft?

Cyber theft is a part of cybercrime where the theft of data or information is carried out through the internet or computer.

What are some of the best Open-source Firewalls?

Perimeter 81, Untangle Firewall, OPNsense, IPFire, etc.

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