Folks, I tried to email to SIMH mailing list but I got delivery failure message. I have some network access problems when it messed configuration up overnight because I can't access any with hostnames but only IP addresses. That cause conflict with network manager service. I successfully set up br0 as permanent setting by using nmcli commands. $ nmcli con add type bridge ifname br0 $ nmcli con add type bridge-slave ifname ens33 master br0 $ nmcli con up br0 I tried to set up tap devices but I kept getting connection failure. SIMH simulator can't access tap devices - no operation permit errors. $ nmcli con add type tun ifname tap0 con-name tap0 mode tap owner `id -u` $ nmcli con add type bridge-slave ifname tap0 con-name tap0 master br0 $ nmcli con up tap0 Does anyone know any successful setup by using nmcli for creating tap devices as permanent configuration? I removed some br0 setup from tap-setup.sh and successfully set up tap devices by using ip commands. My modified tap-setup.sh script here: # Using nmcli for creating br0 device first at once # # $ nmcli con add type bridge ifname br0 # $ nmcli con add type bridge-slave ifname ens33 master br0 # $ nmcli con up br0 # Create the TAP network devices /sbin/ip tuntap add dev tap0 mode tap /sbin/ip link set dev tap0 up /sbin/ip tuntap add dev tap1 mode tap /sbin/ip link set dev tap1 up /sbin/ip tuntap add dev tap2 mode tap /sbin/ip link set dev tap2 up /sbin/ip tuntap add dev tap3 mode tap /sbin/ip link set dev tap3 up # bridge in the tap devices /sbin/brctl addif br0 tap0 /sbin/ip addr flush dev tap0 /sbin/brctl addif br0 tap1 /sbin/ip addr flush dev tap1 /sbin/brctl addif br0 tap2 /sbin/ip addr flush dev tap2 /sbin/brctl addif br0 tap3 /sbin/ip addr flush dev tap3 /sbin/brctl show