Giving the VM (guest) exclusive network access.

Discussions related to using VirtualBox on Windows hosts.
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archive23
Posts: 4
Joined: 10. Jan 2010, 04:44
Primary OS: MS Windows XP
VBox Version: OSE other
Guest OSses: Various

Giving the VM (guest) exclusive network access.

Post by archive23 »

Greetings, fellow virtualizers!
First of all I would like to thank the people who made and still make VirtualBox possible, it's one of the most useful tools...
...in the hands of the knowledgeable :)

Those who are 'lesser knowledgeable', ask things like this:

Right now my home has an ADSL connection through a modem which has 3 comps connected: 1 wifi laptop (me) and 2 regular Ethernet connections.
Basically, I want to deny the host any form of internet access, but I do want to allow the VM (and all of its apps within) to connect to the network through WiFi.
Is this possible? If yes, how?

I regard your time and will to respond as great as awesome :D
Also happy new-ish year!
BillG
Volunteer
Posts: 5102
Joined: 19. Sep 2009, 04:44
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows 10,7 and earlier
Location: Sydney, Australia

Re: Giving the VM (guest) exclusive network access.

Post by BillG »

Yes, you can do that. If you 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.
Bill
archive23
Posts: 4
Joined: 10. Jan 2010, 04:44
Primary OS: MS Windows XP
VBox Version: OSE other
Guest OSses: Various

Re: Giving the VM (guest) exclusive network access.

Post by archive23 »

Thanks for the reply, but I must say that I'm a bit confused. I've read up and tried to understand the Bridged Networking section at the manual, but it got me more confused.
Basically with a bridged network, the guest has its own router and therefor the DHCP server to give it the IP address right? But in order to make use of the internet on the guest this way, I'd have to bridge it to my Wireless card (I really hope I'm on the right track on this).

So if I want this thing to work, I'd have to do the following on my host (@ Networking Connections section):
1. Bridge the VirtualBox Host-Only Network with my Wireless Network Connection
2. In the properties of my Wireless Network Connection, uncheck the VirtualBox Bridged Networking Driver
3. Do the opposite in the properties of my VirtualBox Host-Only Network.

Am I getting a bit warmer this way?
BillG
Volunteer
Posts: 5102
Joined: 19. Sep 2009, 04:44
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows 10,7 and earlier
Location: Sydney, Australia

Re: Giving the VM (guest) exclusive network access.

Post by BillG »

No, bridged networking does not have a built-in DHCP server. The NIC in the virtual machine is bridged to the NIC in the physical computer. The filter software determines whether the traffic is addressed to the host or to a guest by examining the MAC address. From a networking point of view, the vm looks like an additional machine on the physical network, just like plugging an additional machine into the switch.

A NIC in a vm which is bridged to the physical network will only see a DHCP server if there is one active on the physical network (such as if you have an ADSL "router" with a built-in DHCP server, or a server on the LAN running DHCP).

To allow the vm to use the physical network but not allow the host machine to do so, you allow the vm to use the physical NIC in the host machine but disallow the host OS from doing so. If you look at the properties of the NIC from the host OS you see a number of check boxes, one of which is VirtualBox Bridged Networking Driver. This is the filter driver which allows the vm to use this physical device. All the other boxes relate to how the guest OS uses the device.

If you leave the check mark in the VBMD box but clear all the other check marks, the vm can still use the physical NIC. Traffic addressed to its MAC address will go to the IP stack in the vm and be processeed. Traffic cannot go to the host OS from this physical NIC because there are no IP protocols enabled on the host for this NIC.
Bill
archive23
Posts: 4
Joined: 10. Jan 2010, 04:44
Primary OS: MS Windows XP
VBox Version: OSE other
Guest OSses: Various

Re: Giving the VM (guest) exclusive network access.

Post by archive23 »

I found out where I was having trouble with, it was the choice of the guest Networking Adapter Type all the time.
Eventually the Intel(R) PRO/1000 T Server Adapter did the trick.

This is great, this way I can install a fresh copy of WinXP as host without giving it internet access and hence not littering it with all the junk it would otherwise collect through regular internet usage. Added to that, the host is also extremely secure because its OS is not connected to the network at all!

I can't thank you enough for your help! :D
KarlKaefer
Posts: 1
Joined: 17. Nov 2010, 16:05
Primary OS: MS Windows Vista
VBox Version: PUEL
Guest OSses: WIn XP

Re: Giving the VM (guest) exclusive network access.

Post by KarlKaefer »

First of all thank you for the information. It was exactly what I was looking for.

Unfortunately it does not work for me.
Background: VB 3.2.6, Host: Windows Vista (sorry not my fault - it's the company ...), Guest: Win XP (that's my fault :-),

I have the VBoxNetFlt Driver in the NIC of my WLAN Properties(Host). If I deselect all properties except the VBox Driver, the VBox (Guest) does not get a "Public" IP Adress but instead a private (169.xxx.xxx.xxx) from VBox. If I also select the IPv4 Property in the NIC of the Host, the Host as well as the guest will get a "Public" IP Address from the DHCP Server.

Tried the different VBox Network drivers like suggested as well but it does not make a difference. Any other ideas?
BillG
Volunteer
Posts: 5102
Joined: 19. Sep 2009, 04:44
Primary OS: MS Windows 10
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Location: Sydney, Australia

Re: Giving the VM (guest) exclusive network access.

Post by BillG »

You could try to find a newer driver for the WLAN card for the host OS. Odd problems like that,especially with wireless cards, are usually driver problems (ie incompatibility between the manufacturer's device driver and the VBox filter driver. The same problems arise with filter drivers for other virtualization products).

If you can't find a fix for DHCP to the guest OS you will need to manually configure it.
Bill
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