We have recently encountered an issue with Wireless Netwoks when utilizing Windows XP Compatibility Mode under Windows 7 and Virtual PC under Windows Vista. The following quote from Ben Armstrong (Microsoft's Virtualization Program Manager) explains why.
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:
- Just throw away all network traffic from the virtual machine - and the virtual machine will behave like it is disconnected.
- 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:
- 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.
- 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
Published Thursday, October 13, 2005 10:19 PM by Virtual PC Guy
Filed under: Virtual PC / Server Tips 'n' Tricks
This basically states that the methods in which the Virtual Network card access the real network card are stricly forbidden by the Wireless Network Security standard. The reason it works on some wireless network hardware and not others is because some wireless hardware does not conform to the Wireless Network Security standard. This means that all secure network hardware will not be compatible with a virtual environment. So if your virtual pc environment IS compatible with your wireless networking hardware, then your network probably is not entirely secure.
A Link to this blog entry can be found here. This issue has only increased our stance against using wireless networks with Office Tools Professional. Wireless networks (typically) are not stable enough for Office Tools to remain 'constantly on'. Any sort of network disruption can cause errors that may result in data loss. This is why we strongly suggest that all Office Tools Professional users utilize any of the modern gigabit wired routers and wired NIC cards that are available on the market today. The cost of setting up a wired network is cheap when compared to that of a wireless network, yet the stability and bandwidth of a gigabit network far surpasses anything a top-of-the-line wireless network can offer.
