More network/hardware than dev but anyway: I use OPNsense as a firewall at home on an embedded system. Had everything set up nicely and appearing to be working fine, quite a lot of things set up (static leases, VLANs with various firewall rules etc. - a fair bit of stuff involved). I noticed my remote system was failing to back up to my local one. Turned out port forwarding wasn't fully working (initial packet got through but nothing else). I noticed this at midnight.

Ran an update to see if that helped - nope. Reboot time then! It made its shutdown noises and I waited 15 minutes before giving up (no noises, no ping response). Took SD card out. Copied a fresh install onto it, thus wiping all settings. Booted up fine, set up my internet connection, all good. Proceeded to configure it. Noticed I couldn't access the internet from my PC, but could from the firewall itself. Rebooted the firewall. It didn't come back up. Argh!

Reinstalled AGAIN. Attached a serial cable and it was complaining about something which sounded like it couldn't read the SD card. Tried another. Nope. Looked online (using phone): known issue to do with boot delays.

Gave up and went to bed at this point (4am).

Next day: Installed it in a VM instead. Still no internet from my PC! Another known issue to do with default gateway not being the PPPoE interface. Got into shell, manually changed the default route. Was then able to update to the latest version which fixes the gateway issue. Rebooted the VM. All good.

Put all my settings back in, this time taking a backup afterward.

Only to discover....

....port forwarding wasn't working properly. Back to square 1.

Poked around with some NAT settings (outbound ones), made no difference, undid those changes and suddenly it started working.

WTF? /waves arms in the air

OPNsense folk were very helpful, producing a new build for me to try within a couple of hours of me asking about the problem.

But days like that, I start to question whether I really enjoy technology as much as I thought I did...