I want to run a a computer emulator like SimH that offers ethernet device emulation via a
tap interface. It should be possible to access the host system and the internet from the emulator, and it should be possible to reach the emulator from the host system.
On older Ubuntu systems it was easy to set this up with a few commands.
With NetworkManager I haven't been able to create a working bridge configuration.
The recipe for Ub 18.04 from 1257262 doesn't work under Ub 20.04. After
sudo nmcli con add ifname br0 type bridge con-name br0
sudo nmcli con add type bridge-slave ifname eno1 master br0
sudo nmcli con modify br0 bridge.stp no
sudo nmcli con up br0
I get for the last command the output
Connection successfully activated (master waiting for slaves)
nmcli c gives
NAME UUID TYPE DEVIC
br0 32fbc4bc-0ed7-49d3-aa32-2c9ed25c666f bridge br0
Wired connection 1 40a4b49b-c44f-3937-a19e-1951efc650a3 ethernet eno1
bridge-slave-eno1 c39ebf5d-6b0a-46d9-bd41-10e2f71e86d1 ethernet --
brctl show gives
bridge name bridge id STP enabled interfaces
br0 8000.000000000000 no
So the interface
eno1 is not a slave of
br0 is not receiving an
IP address from DNS.
Any help or hint on what is wrong here is very welcome.