How-To fully network a guest. Create a TAP/TUN device if you do not already have this: $ sudo mkdir /dev/net $ sudo mknod /dev/net/tun c 10 200 $ sudo /sbin/modprobe tun Run this script to bring up the TAP interface: #!/bin/sh # change to suit your host # ETH0IPADDR=192.168.1.64 GATEWAY=192.168.1.254 BROADCAST=192.168.1.255 # /sbin/ifdown eth0 /sbin/ifconfig eth0 0.0.0.0 promisc up # /usr/sbin/openvpn --mktun --dev $1 --user `id -un` /sbin/ifconfig $1 0.0.0.0 promisc up # /usr/sbin/brctl addbr br0 /usr/sbin/brctl addif br0 eth0 /usr/sbin/brctl addif br0 $1 # /usr/sbin/brctl stp br0 off # /sbin/ifconfig br0 $ETH0IPADDR netmask 255.255.255.0 broadcast $BROADCAST /sbin/route add default gw $GATEWAY Run this script to reset networking after stopping the guest: #!/bin/sh # /sbin/ifdown eth0 /sbin/ifdown br0 /sbin/ifconfig br0 down # /usr/sbin/brctl delbr br0 # /sbin/ifconfig eth0 -promisc /sbin/ifup eth0 # /usr/sbin/openvpn --rmtun --dev $1 Run this script using the scripts above to start KVM with a TAP interface: #!/bin/sh # sudo sh /etc/qemu-ifup tap0 sudo kvm -m 256 -hda /home/syscrshr/img/win2003.img -net nic -net tap,ifname=tap0,script=no,downscript=no sudo sh /etc/qemu-ifdown tap0 # Your guest should be on the network with its own IP address. This is how the network on the host looks: /etc/network/interfaces # Bridged Networking auto lo br0 iface lo inet loopback # Set up interfaces manually iface eth0 inet manual # Bridge setup iface br0 inet dhcp bridge_ports eth0 # ifconfig ...... should show the tap device (tap0) running with the bridge (br0) and network device (eth0) # /etc/init.d/networking restart ..... restarts the network