Q: VirtualBox: Set Network Adaptor for exclusive use of Guest VM In a previous question I asked how to configure m0n0wall in a VM. Now I would like to set a network addaptor in my machine to be used for the guest VM only, that is, not allow any traffic from the host machine to pass through. I have so far been unable to find a way of doing this. I am using VBox 4.0.0.
I have two physical network cards, one which I would like the host to use and one for the guest.
I've tried disabling the two boxes in red (which then disabled the boxes in green) and left the "VirtualBox Bridged Networking Driver" ticked, but this hasn't worked (or maybe I was expecting this to work more easily than I had hoped).

The idea is to have the VM running as a gateway on the host machine.

A: 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.

A: 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.

A: 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.

A: It seems that this is not actually possible as the host network card has to interface with the guest in some way so disabling the features in the card will not work. It is still possible to make a m0n0wall/gateway in a VM though.

A: I was the same problem with my corporate Windows 7 machine.
I have got two Ethernet connections, one link to my work network and another linked to a DSL router. This second is the connection than I use for my Virtual Box machines.
So, when I plugged the DSL connection my work applications stopped to work properly.
Better than change the cost routes from command line I found the second response coming from uSlackr the most easy and better solution, unchecking all except:


*

*Virtual PC Network Filter Driver

*VirtualBox Bridged Networking Driver


Of course, I use Bridged Adapter option on Virtual Box for the DSL adapter
Now all works like a charm!

A: With a Linux host you'll need to use bridged on the guest, and disable auto connect on the host. 
Host using Mate/Gnome: 


*

*open setting for the interface. 

*Select General 

*Uncheck "Automatically connect to this network"


VM/Guest 


*

*Use Bridged Adapter option


A: Perhaps this:
VBoxManage modifyvm GuestNameHere --natbindip1 'IPofSpecificAdapterHere'
Via https://www.virtualbox.org/manual/UserManual.html#nat-bind-sockets via https://forums.virtualbox.org/viewtopic.php?p=459665#p459665.
