Device connects to the first listed network that is in range.
Auth key (tskey-auth-...) to join your tailnet. Used when the MQTT broker lives inside it (100.x address). Bind writes the key alone and the device wipes its old registration and connects right away — the stored key is never read back; leave empty when saving other settings to keep it.
Whisper-compatible endpoint. Sent on save, applied after device reset.