I'm using ubuntu 12.04LTS I setup a bridged network: # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet dhcp auto br0 iface br0 inet dhcp bridge_ports eth0 bridge_stp off bridge_fd 0 bridge_maxwait 0 Seems to work. Then I created a virtual machine using Ubuntu's vmbuilder tool like so: vmbuilder kvm ubuntu \ --suite 'precise' \ --flavour 'virtual' \ --arch 'amd64' \ --dest 'myvm' \ --hostname 'myvm' \ --mem '2048' \ --rootsize '4096' \ --swapsize '1024' \ --mirror 'http://archive.ubuntu.com/ubuntu' \ --name 'MyName' \ --user 'myuser' \ --pass 'password' \ --bridge 'br0' \ --addpkg acpid \ --addpkg vim \ --addpkg openssh-server \ --addpkg avahi-daemon \ --libvirt 'qemu:///system' \ --ip '192.168.0.100' It generates fine and starts up seemingly without a problem as well when I run virsh start myvm I am then able to resolve it's IP with MDNS and try ping myvm.local So presumably the VM is running? But for some reason I can't communicate with it, I can't SSH in, I don't even get a response to my ping. Any ideas? I'd be happy to provide further information. Thanks.