Virtual Networking and Wireless network adapters

Virtual Networking and Wireless network adapters

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Some people have noticed that our support for virtual networking when using a physical wireless network adapter is a bit hit and miss. 

The reason for this is because in order to perform our virtual networking - we implement an OSI layer 2 filter driver that creates network packets with the MAC address of the appropriate virtual machine.  Unfortunately the wireless networking standard explicitly forbids the creation of network packets with different MAC addresses to that of the physical computer (for security reasons).  To handle this - when we detect that we are using a wireless network adapter we create packets where some of the MAC addresses in the packet match that of the virtual machine - while the other MAC addresses match that of the physical computer.

Given this approach we find that some wireless networking hardware works, but other hardware doesn't.  When it doesn't work it will either:

  1. Just throw away all network traffic from the virtual machine - and the virtual machine will behave like it is disconnected.

    or

  2. Think that the network traffic from the virtual machine is actually coming from the physical computer.  This will cause things like the virtual machine being assigned the same IP address as the physical computer.

If you are seeing either of these symptoms your options are:

  1. Try different wireless networking hardware (either at the wireless adapter or the wireless access point).  I would only recommend doing this if you have the hardware handy.

  2. Use Shared networking under Virtual PC - or the Microsoft loopback adapter and Internet connections sharing with either Virtual Server or Virtual PC (as discussed here: http://blogs.msdn.com/virtual_pc_guy/archive/2005/10/04/477195.aspx).

Cheers,
Ben

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  • Hello Ben,

    I have exactly this problem!!!

    I have a Netgear DG834 Wireless modem/router.

    On my PC I have a PCI Wireless adapter (Netgear WG311).

    The Host PC (Windows XO SP2) run a Virtual PC 2004 Guest PC (Windows 2000 Sp4).

    The Guest use the PCI Wireless Adapter and I can't setup a WORKGROUP and folder share between Host and Guest PC.

    On the "Management->Connected Peripherals" tab of the router I can see sometimes the Host PC, sometimes the Guest PC and sometimes both Host and Guest PC... and both have the same MAC Address!

    The probleam is that I need the Guest PC can see a third PC on my little LAN... because I must do a remote debugging of a VB6 application run on this PC from visual studio 6 running on Windows 2000 as guest PC on Virtual PC.

    There is a trick to solve this problem without buy new hardware :-( or connect the LAN via Ethernet cable?

    Thanks,

    Lorenzo (from Italy)
  • Very interesting. I've been testing NDIS drivers inside VMs but had assumed that i couldnt do it on wireless. Good to know that i can.

    The part that i dont understand is "we create packets where some of the MAC addresses in the packet match that of the virtual machine - while the other MAC addresses match that of the physical computer."

    There are 2 MAC addresses in the ethernet header - the source and destination, and you cant change the destination mac address.

    Or are these the mac addresses in the 802.11 header (i believe there are 4 addresses there) ?

    Thanks.
  • Try http://wlancontroller.com to turn windows 7 into hotspot

  • Probably this is problem with router configuration -> option Bind IP to MAC. After switch OFF this option connection working OK at VPC over Wifi card :-)

  • Yes, I tested. Options Bind IP to MAC + Strict bind (even without added IP-MAC pair to bind list) will disable connection on VPC over Wifi.

  • its nice idea for using internet but not for using wirless card options itself and using software

  • >>Max 20 May 2012 6:49 AM

    >>Probably this is problem with router configuration -> option Bind IP to MAC. After switch OFF this option >>connection working OK at VPC over Wifi card :-)

    >>

    >>Max 20 May 2012 7:33 AM

    >>Yes, I tested. Options Bind IP to MAC + Strict bind (even without added IP-MAC pair to bind list) will disable >>connection on VPC over Wifi.

    Thankyou very much to Max who solved my problem.

    I setup Bridged Networks on VirtualBox. They did not work until i removed ALL MAC/IP bindings on my Netgear 834 router. After that, everything works like a charm.

    Paolo

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