Advancing Network Security: The Power of Open Source Firewalls and Zenarmor
Sep 2023



       MackTech Biz

Advancing Network Security: The Power of Open Source Firewalls and Zenarmor

In an era characterized by ever-evolving cyber threats, the importance of robust network security cannot be overstated. One of the key tools in the arsenal of network defenders is the firewall, and Open Source Firewalls have emerged as versatile and cost-effective solutions. When combined with the right plugins, they can transform into Next-Generation Firewalls (NGFWs) that offer enhanced security features and protection. In this article, we will explore the realm of Open Source Firewalls, with a particular focus on OPNsense, a rising firewall player in the field. We will then delve into the concept of NGFWs and introduce Zenarmor, a recommended NGFW plugin. Finally, we will discuss the relevance of NGFWs in both home and small-to-medium-sized business (SMB) settings.

Unveiling Open Source Firewalls

Understanding Open Source Firewalls

Open Source Firewalls, at their core, are security mechanisms that enforce access control policies between trusted internal networks and untrusted external networks, such as the internet. They possess several key characteristics:

  • Definition and Key Characteristics: Open Source Firewalls are built upon open-source software, offering transparency, flexibility, and affordability.
  • Advantages and Limitations: The advantages include cost-effectiveness, community-driven development, and customization. Limitations include the need for in-house expertise and potential complexities in setup.


Popular Open Source Firewall Solutions

Several Open Source Firewall solutions have gained prominence:

  • OPNsense: OPNsense, based on the FreeBSD operating system, boasts an impressive feature set that includes firewall rules, VPN support, intrusion detection, web filtering, high availability, and user authentication.

  • pfSense: Another FreeBSD-based firewall, pfSense, is known for its robust security features and scalability.

  • IPFire: IPFire, a Linux-based firewall distribution, focuses on high security and ease of use.

  • Endian Firewall: This Linux-based firewall offers comprehensive security features, including VPN support and intrusion detection.


OPNsense - A Rising Open Source Firewall

OPNsense is a formidable open-source firewall and router platform that has gained recognition for its robust feature set, performance, and user-friendly interface. Built on the foundation of the FreeBSD operating system, OPNsense offers a comprehensive suite of tools and capabilities designed to fortify network security and management. Here's a closer look at the key aspects of OPNsense:

The FreeBSD-Based Architecture

OPNsense's underpinning is FreeBSD, a highly regarded and trusted Unix-like operating system. This choice of foundation provides OPNsense with several advantages:

  • Stability and Reliability: FreeBSD is celebrated for its stability, security, and reliability, making it an excellent choice for a firewall and router platform.

  • Performance: The lightweight nature of FreeBSD ensures efficient resource utilization, enabling OPNsense to deliver high performance even on modest hardware.

A Comprehensive Feature Set

OPNsense distinguishes itself with its extensive set of features, making it a versatile solution for network security and management. These features include:

  • Firewall Rules: OPNsense allows users to create highly customizable firewall rules to govern traffic flow within the network. This capability facilitates network segmentation and ensures that traffic adheres to specific policies.

  • VPN Support: Secure remote access is made possible through OPNsense's support for Virtual Private Networks (VPNs). It enables the creation of secure connections for remote users and branch offices.

  • Intrusion Detection and Prevention: OPNsense incorporates Intrusion Detection System (IDS) and Intrusion Prevention System (IPS) capabilities. This means it can identify and respond to suspicious and potentially harmful network activities in real-time.

  • Web Filtering: The platform includes web filtering features, enabling administrators to control internet access, block malicious websites, and enforce web usage policies.

  • High Availability: To ensure uninterrupted network operation, OPNsense supports high availability configurations. This means that in the event of hardware failure or network issues, there is automatic failover to a backup system.

  • User Authentication: OPNsense supports user authentication and access control. This means administrators can implement user-based policies, providing a granular level of control over network resources.

  • 3rd party plugins support: supports via 3rd party community plugins.


User-Friendly Interface

While OPNsense offers advanced security features and capabilities, it is also known for its user-friendly web-based interface. The intuitive dashboard and menu system make it accessible to both experienced network administrators and those who are new to network security management.

OPNsense's robust architecture, comprehensive feature set, and user-friendly interface position it as a leading open-source firewall and router platform. Whether used in small-scale home networks or larger business environments, OPNsense offers the tools needed to establish effective network security measures and ensure the integrity and privacy of network communications. Its flexibility and support for plugins and extensions further enhance its capabilities, making it a compelling choice for those seeking a powerful yet accessible open-source firewall solution.


The Emergence of Next-Generation Firewalls (NGFWs)

Defining Next-Generation Firewalls

Next-Generation Firewalls take traditional firewall capabilities to the next level:

  • Beyond Traditional Features: NGFWs offer deep packet inspection (DPI) and advanced security features.

  • Deep Packet Inspection (DPI): DPI involves analyzing the content of network packets to detect and block advanced threats.

Advanced Security Features

NGFWs offer a suite of advanced security features, including:

  • Application Layer Filtering: Identify and control applications and services running on the network.

  • Threat Intelligence Integration: Collaborate with threat intelligence feeds for real-time updates.

  • User and Device Identification: Tie network activity to specific users and devices for more precise security policies.


Transforming Open Source Firewalls into NGFWs

The Path to Next-Generation Capabilities

Transforming an Open Source Firewall into an NGFW involves several steps:

  1. Enable Deep Packet Inspection (DPI): Configure DPI to inspect and filter traffic based on application signatures and content.

  2. Integrate Threat Intelligence Feeds: Subscribe to threat intelligence feeds and configure the firewall to block known malicious IP addresses and domains.

  3. Implement User and Device Awareness: Integrate authentication mechanisms and tie network activity to specific users and devices.

  4. Utilize Advanced Threat Protection: Add antivirus and anti-malware services to protect against emerging threats.

  5. Regular Updates and Monitoring: Continuously update and monitor the firewall's security rules and configurations to adapt to evolving threats.


Zenarmor - Empowering Open Source Firewalls

Zenarmor's Role as an NGFW Plugin

Zenarmor is a potent NGFW plugin designed to enhance the capabilities of Open Source Firewalls. Key features include:

  1. Application Control
  2. Cloud Application Control (Web 2.0 Controls)
  3. Advanced Network Analytics
  4. Web Filtering and Security
  5. Cloud Threat Intelligence
  6. User-based Filtering and Reporting
  7. Active Directory Integration
  8. RESTful API
  9. Cloud based centralized management & Reporting
  10. Application / Web category based Traffic Shaping and Prioritization
  11. Policy based filtering and QoS
  12. Encrypted Threats Prevention
  13. All-ports full TLS Inspection (for every TCP port, not just HTTPS) -coming soon.


Zenarmor Supported Platforms

Zenarmor is currently available for:

  • OPNsense® (OPNsense 19.x - 23.x, fully integrated into the OPNsense WebUI)
  • FreeBSD® (FreeBSD 11,12,13)
  • Ubuntu Linux (Ubuntu 18.04 LTS, 20.04 LTS, 22.04 LTS)
  • CentOS Linux (Centos 7, 8)
  • Debian Linux (Debian 10, 11)
  • pfSense ® software (pfSense ® software 2.5.x-2.6.x)
  • AlmaLinux (AlmaLinux 1)
  • Rocky Linux (Rocky Linux 9)
  • RedHat Enterprise Linux (RHEL 8.5-9)
  • Amazon Linux (Amazon Linux 2)

Zenarmor deployments on all Linux platforms as well as on FreeBSD-based firewalls can be managed together and seamlessly from the same pane of glass:

Centralized Cloud Management Portal:

Zenarmor can deploy onto any Cloud environments either as a gateway or on a per-server basis.


Hardware Requirements

Active Devices Maximum WAN Bandwidth Minimum Memory Minimum CPU
0 - 50 300 Mbps 1 GB A Dual-Core CPU (x86_64 compatible, single core PassMark score of 200) Note: Deciso A10s and AMD G-SERIES SOC GX Series, Celeron J Series are compatible
50-100 500 Mbps 10 Kpps 4 GB Intel Dual-Core i3 2.0 GHz (2 Cores, 4 Threads) or equivalent
100-250 1 Gbps 20 Kpps 8 GB Intel Dual-Core i5 2.2 GHz (2 Cores, 4 Threads) or equivalent
250-1000 1-2 Gbps 40 Kpps 16 GB Intel Dual-Core i5 3.20 GHz (2 Cores, 4 Threads) or equivalent
1000-2000 1-2 Gbps 32 GB Intel Quad-Core i7 3.40 GHz (4 Cores, 8 Threads) or equivalent
2000+ 2-4.5 Gbps 64GB Intel Quad-Core i9 3.0 GHz (24 Cores, 48 Threads) or equivalent



The Relevance and Cost-Efficiency of Open Source Firewalls with Commercial NGFW Plugins

The Relevance of Open Source Firewalls

Open Source Firewalls have become increasingly relevant in the contemporary cybersecurity landscape. They offer transparency, flexibility, and cost-effectiveness, making them an attractive choice for organizations and individuals seeking robust network security solutions. These qualities are particularly relevant in today's world, where threats are constantly evolving, and budget considerations are more critical than ever.

Why Open Source Firewalls Matter

  1. Affordability: Open Source Firewalls, at their core, are cost-effective solutions. They eliminate the need for expensive licensing fees, making them accessible to a wide range of users, including home users, SMBs, and budget-conscious enterprises.

  2. Customization: The open-source nature of these firewalls allows users to tailor their security measures to their specific needs. This customization ensures that security policies align precisely with an organization's requirements, enhancing overall effectiveness.

  3. Community-Driven Development: Open Source Firewalls benefit from a thriving community of developers and users who continually contribute to their improvement. This collaborative effort results in timely updates, patches, and the incorporation of cutting-edge security features

The Efficiency of Combining Open Source Firewalls with Commercial NGFW Plugins

While Open Source Firewalls offer a strong foundation for network security, their capabilities can be further enhanced by integrating commercial NGFW (Next-Generation Firewall) plugins. These plugins bring advanced security features and threat intelligence to the table, providing a level of protection that rivals dedicated commercial NGFW firewalls without breaking the bank.

Key Benefits of Commercial NGFW Plugins

  1. Advanced Threat Protection: Commercial NGFW plugins often include advanced threat protection mechanisms such as deep packet inspection (DPI), application control, and real-time threat intelligence feeds. These features help detect and mitigate sophisticated threats effectively.

  2. User-Friendly Management: Commercial plugins typically come with user-friendly interfaces that simplify the management of complex security policies. This ease of use allows organizations to maximize the value of their security investments without the need for extensive training.

  3. Compliance and Reporting: Many commercial NGFW plugins offer robust compliance reporting and auditing capabilities, essential for organizations that need to meet regulatory requirements. These features help maintain a secure and compliant network environment.

  4. Integration with Existing Infrastructure: Commercial plugins are designed to seamlessly integrate with popular Open Source Firewall solutions like OPNsense, enhancing their capabilities without the need for significant infrastructure overhauls.


Cost-Efficiency Compared to Dedicated Commercial NGFW Firewalls

The combination of Open Source Firewalls with commercial NGFW plugins like Zenarmor delivers a high level of security at a fraction of the cost when compared to dedicated commercial NGFW firewalls. This cost-efficiency makes it an attractive option for businesses and individuals who want to strengthen their network security without straining their budgets.

Open Source Firewalls, when augmented with commercial NGFW plugins, strike a balance between cost-efficiency and robust security. They offer the flexibility to adapt to evolving threats and the agility to customize security policies to specific needs. This approach enables organizations, including home users, SMBs, and budget-conscious enterprises, to stay ahead of the cybersecurity curve without incurring exorbitant expenses. In a world where network security is paramount, the combination of Open Source Firewalls with Zenarmor commercial NGFW plugins emerges as a compelling and practical choice for safeguarding digital assets while preserving financial resources.


Are you ready to try Opensource Firewall and Zenarmor for yourself?

If you are new to Zenarmor and would like to explore the great capabilities that Zenarmor has to offer, you can simply sign-up and start your Zenarmor® Business Edition 15-day trial, with no credit cards required.

Alternatively, feel free to contact us at and ask for assistance on getting your free trial setup and get started today. We’d love to hear from you! MackTechBiz is an Official Philippines' Partner of Zenarmor.


  • 27 Sep 2023 MackTechBiz

    Hi Patrick, Thank you for the visit. If you have further more question, you can reach us via

  • 27 Sep 2023 Patrick Paul

    This article is very clear and guided me much on deciding about Opensource Firewall and using mini pc or any other firewall appliance I have in the office, this is worth a try. Thank you so much

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