Welcome back! If you saw my last video, you know I’ve been working with the ZimaBoard 832—a small but mighty single-board computer that's perfect for home lab projects. In that video, I introduced the board and talked about why I chose it. If you haven’t watched that yet, check it out here (ZimaBoard 832).
Today, I’m installing OPNsense on the ZimaBoard to act as the firewall for my lab environment. I’ll walk you through the entire process—from downloading the ISO, checking its integrity, burning it to a USB stick, setting up the physical hardware, and finally installing and accessing the OPNsense GUI. But before we jump into the technical stuff, let’s talk a little about why I’m doing this and why OPNsense is the firewall I went with.
Why OPNsense?
OPNsense is an open-source firewall and routing platform based on FreeBSD. It was created as a fork of pfSense with the goal of offering a more secure, modern, and regularly updated alternative. I’ve used pfSense before, but this time around, I wanted to try OPNsense because of its clean web interface and strong plugin ecosystem.
Unlike some firewall solutions that feel outdated or overly complicated, OPNsense has a responsive and intuitive UI. Managing rules and navigating the system feels straightforward. Plus, out of the box, it comes packed with features like IDS/IPS, a proxy server, and two-factor authentication. That’s a solid toolkit for a lab or even a small business environment.
Why Bother with a Firewall in a Lab?
You might be wondering—do I really need a firewall in my lab setup? Technically, no. But should you have one? Absolutely.
Even if your lab isn’t exposed to the internet, you’re likely experimenting with services, testing applications, and configuring devices. That means you’ll inevitably make mistakes. A firewall helps isolate those mistakes and reduces the risk of exposing other devices on your network.
It also introduces network segmentation. Instead of having all your devices on one flat network, a firewall lets you separate your services into logical zones—making your environment safer and giving you valuable experience managing real-world security concepts.
Step 1: Downloading the OPNsense ISO
First, I headed over to the OPNsense website and downloaded the appropriate ISO image for my hardware. In my case, I needed the DVD ISO installer. I also made sure to grab the SHA-256 checksum listed on the site. It's a good habit to verify the integrity of the file you’re downloading—especially something as critical as a firewall OS.
To do that, I used PowerShell on my Windows PC:
- Get-FileHash -Algorithm SHA256 -Path "C:\Path\To\Your\File.iso"
I compared the hash it gave me to the one listed on the OPNsense website. Everything matched—so we’re good to go
Step 2: Extracting the ISO (Why 7-Zip Helps)
Even though Windows has a built-in extraction tool, I ran into some issues when trying to extract the downloaded file. So, I used 7-Zip instead. It worked without a hitch and gave me access to the ISO file inside the compressed archive.
Step 3: Burning the ISO to USB
For this step, I used balenaEtcher, though Rufus works just as well. After launching Etcher, I selected the OPNsense ISO, chose my USB drive, and clicked “Flash.” Once that was done, I had a bootable USB ready to go.
Step 4: Connecting the Hardware
Here’s what the basic hardware setup looked like:
- Power cable to the ZimaBoard
- WAN cable from my ISP router to one of the ZimaBoard’s Ethernet ports
- LAN cable from another Ethernet port to a small POE switch
- My laptop connected to the switch to access the GUI later
- Micro HDMI cable to a display for the initial setup
- USB keyboard for interacting with the BIOS and installer
- Bootable USB with OPNsense
There’s no power button on the ZimaBoard, so powering it off means unplugging it. Once I had everything hooked up, I powered the board and entered the BIOS to set the USB as the first boot device.
Step 5: Installing OPNsense
With the boot order set, the ZimaBoard booted into the OPNsense installer. I didn’t need to manually assign interfaces right away—it automatically recognized them. The installer presented two user options:
- Installer: used to launch the installation process
- Root: used later for managing the firewall
I selected the ZFS file system and used a stripe configuration since I only had one internal drive. Once the installation was complete, I reset the root password, removed the USB, and rebooted the device.
Step 6: Accessing the GUI
After the reboot, OPNsense displayed both the WAN and LAN IP addresses. I connected my laptop to the LAN switch, opened a browser, and entered the IP(192.168.1.1). Boom—I was in.
From there, I could configure interfaces, set up rules, and begin locking things down for the lab.
Final Thoughts
This setup is just one piece of a larger lab I’m building. I wanted something lightweight, affordable, and flexible—and the ZimaBoard + OPNsense combo has delivered so far.
In the next video, I’ll walk you through the current state of the lab and break down how much I’ve spent getting it all together. There’s a lot more to come—server setup, service deployment, and all the fun sysadmin stuff.
Thanks for hanging out, and as always—stay geeking. Peace!
