How to create a bridge network on a Raspberry Pi 4?

I want to run Home Assistant in a VM within my Raspberry Pi 4, so I can also run other things on it. Following directions on the Linux install,, while creating the VM it says:

  1. Under Network Selection, select your bridge.

However I don’t have a bridge. How do I create a bridge network on a Raspberry Pi 4, so HA can listen on port 8123?

Update: This page describes how to use nmtui to create and configure the bridge with a wired ethernet port. You configure your existing wired ethernet port as a “slave” of the bridge, then the bridge gets the IP address instead of your ethernet port.

However, this says:

Note that a bridge cannot be established over Wi-Fi networks operating in Ad-Hoc or Infrastructure modes. This is due to the IEEE 802.11 standard that specifies the use of 3-address frames in Wi-Fi for the efficient use of airtime.

Using NAT with port forwarding looks to be complicated (iptables). So I think I’ll just have to use a separate dedicated Raspberry Pi for my Home Assistant.