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Hyper-V and Windows 8

    Question

  • I am having a ton of difficulty with Windows 8 and Hyper-V Virtual Switch. On several different computers, I have tested using the same configuration:

    1) ENable Hyper-V in Windows 8.

    2) Create an external Virtual Switch and have management host share connection.

    3) Windows 8 host only has 1 NIC.(Laptops, etc.)

    ***As soon as I create the external switch, I lose my internet connection on the host however; the virtual machine connects to the internet fine.

    I need BOTH the host and VM to share the external switch and have 100% internet connectivity.

    Wednesday, February 20, 2013 5:50 PM

Answers

  • Hi,

    We has some discussions related to such problem, same issue happened in Windows 8 laptop, but the NICs they used was wireless NIC, not wired NIC in your scenario.

    Virtual switch in Hyper-V is a “layer-2 switch,” which means that it switches using the MAC addresses that uniquely identify each (physical and virtual) network adapter card. The MAC address of the source and destination machines are sent in each Ethernet packet and a layer-2 switch uses this to determine where it should send the incoming packet. An external virtual switch is connected to the external world through the physical NIC. Ethernet packets from a VM destined for a machine in the external world are sent out through this physical NIC. This means that the physical NIC must be able to carry the traffic from all the VMs connected to this virtual switch, thus implying that the packets flowing through the physical NIC will contain multiple MAC addresses (one for each VM’s virtual NIC). This is supported on wired physical NICs (by putting the NIC in promiscuous mode), but not supported on wireless NICs since the wireless channel established by the WiFi NIC and its access point only allows Ethernet packets with the WiFi NIC’s MAC address and nothing else. In other words, Hyper-V couldn’t use WiFi NICs for an external switch if we continued to use the current virtual switch architecture.

    This is limited by current virtual switch architecture, but just as mentioned above, this theory doesn’t apply to wired NICs.

    Recheck your NIC configuration and give us feedback for further troubleshooting.

    In case your wired NICs truly have such issue you may try following workaround, create an Internal Network switch, and then create network bridge between physical NIC and virtual internal network NIC. Assign internal network for virtual machine, VMs can get external network connection through the network bridge.

    For more information please refer to following MS articles:

    Bringing Hyper-V to “Windows 8”
    http://blogs.msdn.com/b/b8/archive/2011/09/07/bringing-hyper-v-to-windows-8.aspx
    Hyper-V: How to Run Hyper-V on a Laptop
    http://social.technet.microsoft.com/wiki/contents/articles/185.hyper-v-how-to-run-hyper-v-on-a-laptop.aspx

    Hope this helps!

    TechNet Subscriber Support

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    Lawrence

    TechNet Community Support

    Thursday, February 21, 2013 2:45 AM
    Moderator

All replies

  • We've not had any issues.

    What NIC is installed in these machines?

    Make sure the BIOS on the board is up to date and the NIC drivers are the most current.

    vSwitch in NIC Properties

    Hyper-V Management vSwitch Settings

    The above is how we have Hyper-V set up on all Win8 machines including laptops where in some cases the vSwitch is WiFi connected.


    Philip Elder SBS MVP Blog: http://blog.mpecsinc.ca

    Wednesday, February 20, 2013 6:06 PM
  • I have confirmed the same settings. I have a Realtek adapter in an ASUS MoBo and an Intel adapter integrated within Intel MoBo. Identical issues on BOTH machines.

    It appears Windows 8 does not use the new vEthernet adapter created by the new External Network switch. I have restarted and the same issue persists.

    After frustration, I have removed the Virtual switch, and created a new one. The newly created vEthernet switch defaults to DISABLED. After another restart, everything appears to be working. Something is not right about this however; it appears to be working now. I will try the same removal and re-creation of the external virtual switch on my other hosts.

    Thanks for the prompt reply!

    -Joe

    Wednesday, February 20, 2013 6:37 PM
  • Hi,

    We has some discussions related to such problem, same issue happened in Windows 8 laptop, but the NICs they used was wireless NIC, not wired NIC in your scenario.

    Virtual switch in Hyper-V is a “layer-2 switch,” which means that it switches using the MAC addresses that uniquely identify each (physical and virtual) network adapter card. The MAC address of the source and destination machines are sent in each Ethernet packet and a layer-2 switch uses this to determine where it should send the incoming packet. An external virtual switch is connected to the external world through the physical NIC. Ethernet packets from a VM destined for a machine in the external world are sent out through this physical NIC. This means that the physical NIC must be able to carry the traffic from all the VMs connected to this virtual switch, thus implying that the packets flowing through the physical NIC will contain multiple MAC addresses (one for each VM’s virtual NIC). This is supported on wired physical NICs (by putting the NIC in promiscuous mode), but not supported on wireless NICs since the wireless channel established by the WiFi NIC and its access point only allows Ethernet packets with the WiFi NIC’s MAC address and nothing else. In other words, Hyper-V couldn’t use WiFi NICs for an external switch if we continued to use the current virtual switch architecture.

    This is limited by current virtual switch architecture, but just as mentioned above, this theory doesn’t apply to wired NICs.

    Recheck your NIC configuration and give us feedback for further troubleshooting.

    In case your wired NICs truly have such issue you may try following workaround, create an Internal Network switch, and then create network bridge between physical NIC and virtual internal network NIC. Assign internal network for virtual machine, VMs can get external network connection through the network bridge.

    For more information please refer to following MS articles:

    Bringing Hyper-V to “Windows 8”
    http://blogs.msdn.com/b/b8/archive/2011/09/07/bringing-hyper-v-to-windows-8.aspx
    Hyper-V: How to Run Hyper-V on a Laptop
    http://social.technet.microsoft.com/wiki/contents/articles/185.hyper-v-how-to-run-hyper-v-on-a-laptop.aspx

    Hope this helps!

    TechNet Subscriber Support

    If you are TechNet Subscription user and have any feedback on our support quality, please send your feedback here.

     


    Lawrence

    TechNet Community Support

    Thursday, February 21, 2013 2:45 AM
    Moderator
  • Well...after coming home tonight and attempting to access the internet, I fail. Although it was working fine earlier today, it appears that the same issue arises: No internet connection on host but the VM works fine.

    I have tried your workaround by bridging the Internal and Ethernet NIC adapters together and this appears to be working fine after a reboot. Thank you for the suggestion. I will be attempting this on a Lenovo Yoga 13 laptop tomorrow. The goal is to get something like XP mode configured so a user can access his VPN connection using XP (Because I.T. has not upgraded hardware to be compatible with Windows 8 yet)

    -Joe

    Thursday, February 21, 2013 4:41 AM
  • Hi,

    I would like to confirm what is the current situation? Have you tried the workaround on that Lenovo Laptop, what's the result?

    If there is anything that we can do for you, please do not hesitate to let us know, and we will be happy to help.


    Lawrence

    TechNet Community Support

    Monday, February 25, 2013 2:50 AM
    Moderator
  • Yes...the Bridge between the wireless adapter and the INTERNAL virtual adapter appears to be the workaround on the Lenovo. As for the desktops, I needed to REMOVE my Virtual switches from Hyper-V altogether so I can use the internet on the Windows 8 Host PC. I had to do this because I had trouble with the bridge and host internet access again.
    Monday, February 25, 2013 4:30 AM