[HOW-TO] Bridge Network Interface in VirtualBox

When U install VirtualBox and need to connect to your Guest box with an IP in the same range that you using not the range that VirtuaBox (Which using DHCP and you Host box acts like the DHCP Server for the guest boxes different range and the actual IP of the guest box is the same of your host box ip).

If you have the same problem so this is the how to you looking for :D.

Let's Start First you have to install VirtualBox :p if u did not install it it's simple. 

sudo apt-get install virtualbox
Now let's go the real work :o :)


Step 1
You need to install "bridge tools" and "User-mode Linux (utility programs)" 


     sudo apt-get install uml-utilities bridge-utils



Step 2
Create a TAP Interface 

     sudo tunctl -t tap1 -u username
and username is your username (eg. in my case it's bahaa)
so i should type 
 sudo tunctl -t tap1 -u bahaa


Step 3
Create the Bridge 
      sudo brctl addbr br0
as br0 is the bridge interface name (you can name it as u like)


Step 4
You need to set your network interface in promisc mode "this means it's shared with all interfaces connected to it" in our case will be the bridge interface br0 
      sudo ifconfig eth0 0.0.0.0 promisc


Step 5
Now we will link our real interface eth0 to the bridge interface br0 
      sudo brctl addif br0 eth0


Step 6
Assign an IP to the br0. If you are using DHCP 
     sudo dhclient br0
Or, if you assign an IP yourself 
     sudo ifconfig br0 192.168.0.100


Step 7
Link TAP to bridge br0 
     sudo brctl addif br0 tap1


Step 8
Activate TAP interface 
      sudo ifconfig tap1 up


Step 9
Add the default gateway to your bridge interface 
     sudo route add default gw 192.168.0.1 br0
Where 192.168.0.1 is your gateway ip (eg. router ip in most cases).

Step 10
Change the permission of /dev/net/tun 
     sudo chmod 0666 /dev/net/tun


Step 11
At the VirtualBox startup panel, choose “Host Interface” and add “tap1″ to “Interface Name”.


Step 12
At the guest (after boot up the guest OS), change the IP of the guest OS to the same subnet of your host. this is example for
/etc/network/interfaces 


    iface eth0 inet static
    address 192.168.0.101
    netmask 255.255.255.0
    gateway 192.168.0.1
    network 192.168.0.0

    dns-nameservers 208.67.222.222 208.67.220.220

Step 13
Now, you can connect to the guest OS by its IP in VirtualBox.

When you reboot your guest OS, you need to repeat the Step 2 to 10 to Again. Or, you can create a executable script to make your job easy.

Have fun :D
BTW I'm using this way and it works with me in Ubuntu 9.04.

Reference