Home Assistant, Govee Lights Local, VLANs, Oh my!

We recently bought some Govee Glide Hexa Light Panels, because they have a local LAN API that is well integrated into Home Assistant. Or so we thought.

Our network is not that complicated, but there is a dedicated VLAN for IOT devices. Home Assistant runs in a container (with network=host) on a box in the basement, and that box has a NIC in the IOT VLAN so it can reach devices there easily. So far, this has never been a problem.

Enter the Govee LAN API. Or maybe its Python implementation. Not exactly sure who's to blame here.

The API involves sending JSON over multicast, which the Govee device will answer to.

No devices found on the network

After turning logging for homeassistant.components.govee_light_local to 11, erm debug, we see:

DEBUG (MainThread) [homeassistant.components.govee_light_local.config_flow] Starting discovery with IP 192.168.42.2
DEBUG (MainThread) [homeassistant.components.govee_light_local.config_flow] No devices found with IP 192.168.42.2

That's not the IP address in the IOT VLAN!

Turns out the integration recently got support for multiple NICs, but Home Assistant doesn't just use all the interfaces it sees by default.

You need to go to Settings → Network → Network adapter and deselect "Autoconfigure", which will allow your to select individual interfaces.

Once you've done that, you'll see Starting discovery with IP messages for all selected interfaces and adding of Govee Lights Local will work.