I've just switched from Fedora to Debian 12 and I can't seem to get bridge networking to work. I've followed the official guide and edited the /etc/network/interfaces. I double checked and everything is correct. I rebooted the system but my ethernet stopped working altogether. Are there any updated guides and common pitfalls that I should keep in mind.
I need the bridge for kvm.
I can't find my notes on how I got this to work on Debian 11 but, if I recall correctly, I had to disable NetworkManager and setup networking directly via /etc/network/interfaces. I no longer have Debian running but at the time this worked for me:
source /etc/network/interfaces.d/*
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
# allow-hotplug eno1
auto br0
iface br0 inet dhcp
bridge_ports eno1