I'm using Home Assistant OS as a Virtualbox in Windows 10. I'm accessing it via homeassistant.local:8123. So I'm trying to configure my Mosquitto broker in Home Assistant. It wants to know my broker address. I'm guessing I need to use an ip. Where do I find this? Should I use localhost, 127.0.0.1, homeassistant.local or maybe an unused ip like 192.168.1.99 from my router?
If you are following this page, I find it is a bit misleading. Hope the following steps help you.
Install mosquitto (broker)
Suggest follow official github doc to configure mosquitto addon; (This step doesn't require IP configure)
Configure client integration within home assistant
Refer to here for your client integration, use localhost for your ha integration to connect your mosquitto broker;
Configure MQTT client outside home assistant
you need to find the exposed IP of your mosquitto broker, in your case, it shall be your VM's IP.