Hi, I try to configure a kvm with a NIC, but no attached network to this NIC. I tried following methods: 1. Create a generic ethernet connection I configured the VM with following interface section: <interface type='ethernet'> <script path='/root/noscript.sh'/> <target dev='myvm_nic0'/> <interface/> The script /root/noscript.sh exists and is executable and has only an exit 0 statement. When I try to start the VM, virsh aborts with following error: error: Failed to start domain myvm error: internal error process exited while connecting to monitor: qemu-kvm: -netdev tap,script=/root/noscript.sh,id=hostnet1: could not configure /dev/net/tun (tap%d): Operation not permitted qemu-kvm: -netdev tap,script=/root/noscript.sh,id=hostnet1: Device 'tap' could not be initialized The tun module is loaded and I can create tap devices with tunctl. So there might be no problem... 2. I configurerd a network with no forward element. I've defined and started following network on the host with virsh net-define / net-start <network> <name>myvm_isolated</name> <bridge name='virbr_myvm_1' /> </network> The documentation says: "If there is no forward element, the network will be isolated from any other network (unless a guest connected to that network is acting as a router, of course)." The interface configuration of the domain was this: <interface type='network'> <mac address='00:12:67:bb:bb:11'/> <source network='myvm_isolated'/> <model type='e1000'/> </interface> The VM starts as expected. But the interface is connected to an host bridge like a NAT interface. There is a DHCP server in the network and the VM gets an IP Address and can ping and ssh to the VM-Server... I used following version of libvirt and qemu on SuSE Enterprise Linux Server SP2: # virsh version Compiled against library: libvir 0.9.6 Using library: libvir 0.9.6 Using API: QEMU 0.9.6 Running hypervisor: QEMU 0.15.1 Can you please tell me how to configure a not connected (isolated) network interface card for my VM? Regards, Christian