All discussions about the open source, FreeBSD-based firewall called OPNsense.
No clue. :)
You haven't mentioned the logs. Any hints there? System/ log files/ general. You can see there how a regular reboot/ shutdown should look like at least.
Is there a second device at the same outlet, that writes logs or shows its uptime? To rule out power outages.
Bios settings: is there a setting to power on the pc when the power is reconnected. (If it was an outage)
It's plugged into a power strip that other devices are plugged into, I did turn on "power on on ac restore" so if it is power related it should come back and I'll see the downtime in uptimekuma.
The system logs go straight from No IP Change detected to the next boot, so a crash or failure seem likely. If something told the computer to shut down, I should see that in the logs, right?
It's a passively cooled computer, is there any way that I can determine whether a high temp forced the computer down?
The system logs go straight from No IP Change detected to the next boot, so a crash or failure seem likely.
I think so. If it was shut down orderly, there should be log entries for the shutdown.
It's a passively cooled computer, is there any way that I can determine whether a high temp forced the computer down?
Some bios have logging. I remember a Asrock board with bmc which remembered CPU too hot events. It depends on the board, normally I would say: I don't think so.
If it is a hardware issue: boot a Live Linux from an USB-stick. Memtest86, long smart test,fsck, CPU burnin test, a network load test could show failures. But it is just wild guessing at this point from my side. Sorry.
CPU temps in opnsense: system / settings/ misc/ thermal. Not helpful but maybe interesting.