Setting bridge mode on virtualbox ose

1.Install two components on ubuntu jaunty
#sudo apt-get install bridge-utils uml-utilities

2.Write two scripts for start and stop bridge interface
#sudo vim bridge.sh
tunctl -t tap0 -u
brctl addbr br0
ifconfig eth0 0.0.0.0 promisc
brctl addif br0 eth0
dhclient br0
brctl addif br0 tap0
ifconfig tap0 up
chmod 666 /dev/net/tun

#vim bridge-down.sh
brctl delif br0 eth0
brctl delif br0 tap0
brctl delbr br0
ifconfig tap0 down
ifconfig br0 down
ifconfig eth0 down
ifconfig eth0 up

3.Setting virtualbox network to Host Interface
4.Running virtualbox virtual machine