Howdy. I have HAOS running in a Virtualbox VM on a computer on my private subnet (let’s call it the .150 subnet). All my IoT devices are on my .151 subnet. HA can see most of my IoT devices because I’m not currently isolating the subnets, but my vacuum is defying discovery because of UDP crossing the subnets. I’m sure there’s a way to configure the router to allow cross-subnet discovery, but it would just be better all around if HAOS was on the IoT subnet.
Is it possible to make HAOS think it’s on the .151 subnet, even though the host computer for the VM running HAOS is on the .150 subnet?
I’ve read briefly about Virtualbox’s networking features, but I not only know nothing about them, I don’t even know generally whether a VM can be configured to be on a different subnet than it’s host. I would think not, because when I do isolate the subnets, nothing that’s physically on the .151 subnet would be able to see the host computer on the .150 subnet to get to the VM that thinks it’s on the .151 subnet. But I’m guessing.
Also, HA has some network configs:
I changed these from .150 to .151 but simply lost connectivity to HA (thankfully, it’s super easy to restore from a VM snapshot!).
I’d appreciate any help.
Yes, configure it to be one large subnet so that they can all talk to each other
That does wreck your isolation
Host networking would allow the VM to act as if it was another machine on your network and not a machine inside a host. Your physical network card would end up with 2IP addresses
If you want isolation, I would actually go more complex than this and I would give Home Assistant two separate virtual network cards, one which is on the IOT network and one that is not.  you will have to set up priority for them so that it understands which one it should use to go out to the Internet. I’m not actually sure how well Home Assistant handles two network cards, i’d have to look up the info, but it should be able to
If it can’t, you will have to put a reverse proxy in front of it with some fancy rules