When your fibre drops,
your network keeps working.
A tested, step-by-step OPNsense guide to automatic dual-WAN failover — fibre primary, 5G backup. From a serial-console install to the moment it switches on its own.
EN + PT · PDF
One line is one point of failure
A single outage mid-meeting, mid-upload, or mid-exam and you're stuck reconnecting by hand. This guide gives your network a backup that takes over by itself — in seconds, no babysitting, and it switches back when fibre returns.
What's inside
Two clear parts. Exact menu paths for every step. No 40-minute video to scrub through.
Part A — Installation
Make the boot USB, install OPNsense over a serial console (the headless, no-video case), first boot and web access.
Part B — Failover
Gateways and monitoring, the gateway group, and the one LAN rule most tutorials forget — without it, nothing works.
Exact menu paths
Every step lists the precise OPNsense path, so you're never guessing where a setting lives.
A real test method
How to prove it works: pull the cable, time the cutover, confirm the active path.
Troubleshooting table
The usual reasons it doesn't switch — and the exact fix for each.
Honest scope
Straight talk on what this is (link-down failover) and what it isn't (SD-WAN).
I pulled the cable to be sure.
This isn't theory rewritten from a forum thread. I built it on a repurposed, fanless appliance with no video output, set up fibre as the primary link and 5G as the backup, and then validated it the only way that counts — by physically disconnecting the fibre and timing how long until 5G took over.
With the right trigger, the switch lands in seconds. Everything in the guide is the setup that passed that test.
- Homelab and small-office setups that can't afford downtime
- Anyone running OPNsense who wants automatic redundancy
- People who want to understand why each step exists
- Headless appliances with serial-console-only access
Questions
Do I need the exact same hardware?
No. The guide uses a Sophos XG 86 as the reference, but every step adapts to any OPNsense-compatible hardware. If your device has video output, you can skip the serial-console parts entirely.
Is this SD-WAN?
No — and the guide is upfront about that. This is link-down failover with static policy-based routing. It keeps your network up when the primary line dies, which is what most homelabs and small offices actually need.
What exactly do I get?
An 11-page PDF, in both English and Portuguese (same content), delivered instantly after purchase. Install + failover, start to finish.
Will the failover drop my connection?
There's a short cutover window (a few seconds) while the switch happens. The guide explains what survives it and what doesn't, so there are no surprises.
Give your network a backup that just works
Instant download · English + Portuguese · $7
I want this — $7