KVM bridged network like in virtualbox

I am giving you my /etc/network/interfaces file where I configured a bridge to use with four VMs on Ubuntu server which also uses KVM (my default lan card is 3rd i.e. 0,1,2,3 so eth2 is used)

auto lo
iface lo inet loopback

# The primary network interface
auto eth2
iface eth2 inet manual

auto br0
iface br0 inet static
        address 192.168.1.17
        netmask 255.255.255.0
        network 192.168.1.0
        broadcast 192.168.100.255
        gateway 192.168.100.100
        # dns-* options are implemented by the resolvconf package, if installed
        dns-nameservers 192.168.103.2
        dns-search mydomain.com
        bridge_ports eth2
        bridge_fd 9
        bridge_hello 2
        bridge_maxage 12
        bridge_stp off

The above is a correct configuration.You might need to check /etc/network/interfaces manual page http://manpages.ubuntu.com/manpages/hardy/man5/interfaces.5.html to understand what the keyword manual in above does.

Post your network interfaces file where you defined bridge then we will be able to help.

I noticed your eth0 and sw0 are having same Mac address. Bridge works on Layer2 that might be source of your problem (some one correct me if I am wrong) and eth0 has IPv6 address where as sw0 has IPv4 address.This is not correct.

Try this:

1. Setup the virtualbox to use 2 adapters:
   • The first adapter is set to NAT (that will give you the internet connection).
   • The second adapter is set to host only.
2. Start the virtual machine and assign a static IP for the second adapter in Ubuntu (for instance 192.168.56.56). The host Windows will have 192.168.56.1 as IP for the internal network (VirtualBox Host-Only Network is the name in network connections in Windows). What this will give you is being able to access the apache server on ubuntu, from windows, by going to 192.168.56.56. Also, Ubuntu will have internet access, since the first adapter (set to NAT) will take care of that.
3. Now, to make the connection available both ways (accessing the windows host from the ubuntu guest) there's still one more step to be performed. Windows will automatically add the virtualbox host-only network to the list of public networks and that cannot be changed. This entails that the firewall will prevent proper access.
4. To overcome this and not make any security breaches in your setup:
   • go to the windows firewall section, in control panel,
   • click on advanced settings. In the page that pops up,
   • click on inbound rules (left column), then on new rule (right column). Chose custom rule, set the rule to allow all programs, and any protocol. For the scope, add in the first box (local IP addresses) 192.168.56.1, and in the second box (remote IP) 192.168.56.56. Click next, select allow the connection, next, check all profiles, next, give it a name and save.

That's it, now you have 2 way communication, with apache/any other service available as well as internet. The final step is to setup a share. Do not use the shared folders feature in virtualbox, it's quite buggy especially with windows 7 (and 64 bit). Instead use samba shares - fast and efficient.

Follow this link for how to set that up: https://wiki.ubuntu.com/MountWindowsSharesPermanently