Isolated bridge does not bridge

Hello, I want to do some testing and I have removed two VM's from the bridge what connects them to internet, and added them to another isolated bridge what's not connected to internet. Problem is that I cannot reach the other host in the isolated network. Something like this: virsh shutdown kvm66 virsh shutdown kvm68 brctl delif br0 vnet10 vnet6 # the interfaces of kvm66 and kvm68 brctl addbr br1 brctl addif br1 vnet10 vnet6 Then I've replaced br0 to br1 in the XML of both VM's with "virsh edit". Then I did start the VM's using the serial console (no network): virsh start --console kvm66 virsh start --console kvm68 I cannot ping from one machine to the other. Why?? With regards, Paul -- Paul van der Vlis Linux systeembeheer Groningen https://www.vandervlis.nl/