VirtualBox: Set Network Adaptor for exclusive use of Guest VM

I just tested this running an Ubuntu 11.10 Guest on a Windows 7 host with VirtualBox 4.1.16.

I set the guest VM's Virtualbox configuration I set the networking mode to "Bridged", and attached to my host's LAN connection.

On the host, I disabled all but "VirtualBox Bridged Networking Driver" in the connection properties list.

I was subsequently able to access the internet from my guest OS, but not from the host.

My intended use was as a virtual appliance to bypass my university network's requirement for Windows machines to install proprietary tracking software. The university only performs OS Fingerprinting before authentication on the network, so it is possible to boot to Linux, spoof a MAC address, authenticate, reboot into windows, spoof the same MAC address and connect to the network without authentication or tracking software.

I have not yet tested this technique with a virtual OS configured in the manner described above, but I will update my response with complete testing when I do.

Another option would be to get a USB network adapter and have VirtualBox capture that USB device and present it to the guest operating system. That way on the guest will be the only one to be able to access that device directly.

According to this forum post you should try this:

Set the networking to bridged mode. The system adds extra code to allow the NIC in the vm to access the NIC driver. If you look at the NIC properties from the host OS you will see this extra checkbox for the VirtualBox filter driver. If you clear all of the checkboxes except this one, the NIC in the vm can still see physical NIC but the OS in the host can't.