do it yourself firewall free open source software home brew internet networking open source operating system router bsd, embedded, firewall, freebsd, homelab, InternetSecurity, itsecurity, miniitx, nanobsd, netgate, networkappliance, networking, opensource, opnsense, pfsense, router, securehome, SysAdmin, TechDIY, x86 9M2PJU June 15, 2025 0 Comments

Best Small FreeBSD-Based Systems for Routers & Firewalls (x86 Hardware)

Are you planning to build a dedicated firewall or router using x86 hardware? FreeBSD, known for its stability, security, and powerful networking stack, is the foundation for several robust solutions perfect for this task.

In this post, we’ll explore the top FreeBSD-based small operating systems you can install on x86 hardware to transform it into a powerful, reliable, and secure router or firewall.

Why Use FreeBSD for Network Appliances?

FreeBSD is widely respected for its:

Rock-solid performance
Advanced networking features (like PF, IPFW, and netgraph)
Security-focused architecture
Clean, consistent system design

These features make it a preferred base for commercial and open-source router/firewall systems.

1. pfSense® – Trusted and Proven

pfSense is arguably the most popular FreeBSD-based firewall/router OS in the world. Maintained by Netgate, it combines FreeBSD’s power with a user-friendly web interface, making it suitable for both home users and professionals.

Key Features:

Web GUI for full control
Stateful firewall with PF
NAT, port forwarding, VLANs
Built-in DHCP, DNS forwarding, and captive portal
VPN support (OpenVPN, IPsec, WireGuard)
High availability (CARP/HA)
Traffic shaping and Quality of Service (QoS)
Add-on packages (Snort, pfBlockerNG, Squid, etc.)

Minimum Requirements:

x86 or x86_64 CPU
1GB RAM (2GB or more recommended)
4GB storage (SSD preferred)
At least two network interfaces (NICs)

Best Use Cases:

Home firewall/router
Small office or business gateway
Educational networks
VPN edge device

Official Website:
https://www.pfsense.org

2. OPNsense® – Modern and Open Alternative

OPNsense is a community-driven, open-source fork of pfSense. Built on FreeBSD, it offers a more modern user interface, frequent updates, and a plugin system designed for flexibility.

What Makes It Different from pfSense?

Modern and responsive web UI
Faster update cycles (weekly)
HardenedBSD kernel (optional for extra security)
Better plugin framework
Transparent open development model

Notable Features:

IDS/IPS with Suricata
Real-time traffic graphs and reporting
DNS over TLS, DoH, and encrypted DNS options
Built-in 2FA and secure remote management
Easy backup and restore

Ideal For:

Users who want modern UI and faster development
Advanced users who prefer open-source transparency
Businesses that require frequent security updates

Official Website:
https://opnsense.org

3. NanoBSD – Minimal FreeBSD for Embedded Systems

NanoBSD isn’t a separate OS, but a build tool that comes with FreeBSD. It creates minimal, read-only, embedded FreeBSD images for use on devices with limited storage or specialized applications (e.g., routers, kiosks, and appliances).

Features:

Extremely lightweight image (~100–300MB)
Read-only root filesystem (reduces corruption)
Optimized for CF/SD/USB media
Easily upgradable via scripts
Complete control over what goes into the system

Important Notes:

No graphical UI by default
Requires strong FreeBSD knowledge
Manual configuration of services and network interfaces

Best For:

Developers creating custom appliances
Embedded or industrial x86 systems
Learning how FreeBSD works under the hood

Documentation:
https://docs.freebsd.org/en/articles/nanobsd/

Comparison Table

Feature	pfSense	OPNsense	NanoBSD
Based on FreeBSD	✅ Yes	✅ Yes	✅ Yes
Web Interface	✅ Yes	✅ Yes	❌ No
VPN Support	✅ Yes	✅ Yes	❌ Manual Only
IDS/IPS	✅ (Add-ons)	✅ (Suricata)	❌ No
Plugin System	✅ Yes	✅ Yes	❌ No
Beginner Friendly	✅ Yes	✅ Yes	❌ No
For Embedded Devices	⚠️ Not ideal	⚠️ Not ideal	✅ Yes
Frequent Updates	🔁 Moderate	🔁 Weekly	🔁 Manual

Hardware Recommendations

You can run pfSense or OPNsense on many low-power x86 machines, including:

Intel NUCs and mini PCs
Used thin clients (e.g., HP T620 Plus, Dell Wyse)
PC Engines APU series
Small form factor desktops with 2+ NICs

Tip: For best performance and compatibility, always use Intel-based network cards (NICs) — FreeBSD has excellent driver support for them.

Choosing the Right One

If you want…	Choose…
Proven, stable, and well-supported firewall/router	pfSense
A more modern UI and frequent updates	OPNsense
To build a fully customized embedded FreeBSD image	NanoBSD

Final Thoughts

Building your own firewall or router using FreeBSD-based systems is a rewarding project. It gives you:

Full control over your network
Better privacy and security
Valuable knowledge in networking and open-source systems

Whether you choose pfSense, OPNsense, or go all-in with NanoBSD, you’ll be using a robust foundation trusted by professionals worldwide.

All it takes is an old PC or a mini PC, a USB installer, and a bit of time.