I was checking the logs when I noticed the following:
2023-12-18T14:46:06
[Warning]
lldpd unable to create /var/empty/etc directory: Operation not permitted
I tried uninstalling and reinstalling the plugin but it's still the same - wondering if this is why it cannot detect any neighbours. Would manually creating this folder help?
OPNsense 23.7.10_1-amd64
FreeBSD 13.2-RELEASE-p7
OpenSSL 1.1.1w
This "error" is completely harmless noise and has nothing to do with failure to detect neighbours. If the detection fails, it's either blocked by firewall or the protocol is not supported/enabled.
On a semi-related note, you might help to get some traction upstream: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=257330
Thanks, I'll look at that bug report and see if I can add anything useful.
In the meantime I resolved the problem by installing lldpd on the Proxmox host my OPNsense is running on, and now it's seen as a neighbour. It's possible it was working when it was a physical device, but I was trying to figure why my Unifi console was not seeing the firewall as online when it clearly is. This was also the case when it was a physical machine, so the issue is probably with Unifi.