Selecting Bridged Network causes error with UTM on MacOS

I have been struggling with this for a few days now. Here is what I did in a nutshell, based on this post:

  • Installed UTM on my iMac M1 Silicon, MacOS 15
  • Created a virtual machine using the appropriate HA image as per instructions
  • Set the network to Bridged

When I run the VM I get this error message:
QEMU error: QEMU exited from an error: qemu-aarch64-softmmu: -netdev vmnet-bridged,id=net0,ifname=en0: cannot create vmnet interface: general failure (possibly not enough privileges)

I know the installation should be correct because when I used a Shared Network, Home Assistance works, kind of. I could go through all the setup routines etc, however I have all sorts of dramas with detecting and pairing devices as would be expected.

I have tried finding a solution online, but there is very limited information available, and what I found did not work for me. It is frustrating and I don’t know what else to do.

Any help would be greatly appreciated.

I have no knowledge about MacOS and hypervisors, but I have a general knowledge and when using bridge network adapters it is necessary to put the physical network adapter into promiscuous mode.
You might not have a driver installed that allow it or you might not have the rights to set the adapter to that mode.

Thanks for your response WallyR. I had no idea what that means, so I looked it up and it sounds like I would create a security hole that way, which makes me uncomfortable with my limited networking knowledge. Besides all the information I found re promiscuous mode on a Mac is outdated and I couldn’t really find out how to enable it. The ifconfig command apparently used to support it, but Apple took it off a while back.

I have seen VMware and VirtualBox use promiscuous mode, so there must be a way to enable this safely. Do you have any further info?

Meanwhile I did some further testing with just a blank VM on UTM and it throws the error as well, so the issue isn’t really related to HA. Maybe I will see if I can raise the issue with UTM but I am not holding my breath.

Non-promiscuous mode means the net adapter will filter all packets away that are not having the adapter’s own MAC address as destination. This means your adapter can only accept packets for one host/IP address, so you can not run a bridge or switch emulation on that adapter.