Getting Networking to Work in Hyper-V Beta
First, I thoroughly recommend reading Ben Armstrong's article, "Understanding Networking in Hyper-V," for an explanation of how networking changes on a Hyper-V enabled host. He explains that the real NIC on the host is converted to a virtual network switch and a new virtual NIC is created on the host to access the network using the virtual switch.
Sometimes networking doesn't get setup properly on the host when the Hyper-V role is installed. Here's how to fix it:
When networking is not configured properly after Hyper-V is installed, you'll see only the one physical adapter in Network Connections (assuming, of course, that you have only one network adapter).
1. Open network properties of the NIC and uncheck all the connections on the adapter (Client for Microsoft Networks, IPV4, IPV6, ...everything) and click OK. Obviously, this will disrupt network communication to and from the server, so plan this work accordingly. 
2. Click Virtual Network Manager in the Hyper-V console and create a new external network bound to the real NIC. This will convert the real NIC on the host to a Microsoft Virtual Switch and create a new virtual NIC for the host to use for its network adapter (see step 4).
3. In each Hyper-V guest, select the External Virtual Network for the VM's network adapter.
4. Back on the host, you will now see two NICs in the Network Connections window. Local Area Connection (the original real NIC) is now a Microsoft Virtual Switch and is using only the Microsoft Virtual Network Switch Protocol. You will also see a new virtual NIC (usually named "Local Area Connection 3," in my testing). I've renamed it here to Virtual Local Area Connection.
5. Open the properties of the new virtual NIC and re-IP it to it's original static IP address.
6. Verify that the host has network connectivity, and then check your VM guests for connectivity.
Let me know if this helps you.
Labels: Hyper-V, Networking, virtual, Windows Server 2008
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posted by Jeff @ 9:28 AM
19 Comments
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19 Comments:
Your a lifesaver... thank you very much. I couldn't connect to the host from my virtual machines. I turned off all the protocols on the physical machine and now it's working really well. Thanks for the article.
Dude, you rock!
I using Hyper-V with a 2003 Server Std. guest OS. I'm using dynamic IP for the host OS (of course 2008 server). In the last instructions you say to change the Virtual connection to a static IP, and since I'm only doing dynamic I didn't do that step. Anyhow -- I followed your instructions and still nothing on the guest. All the properties in your screen shots of the Host and Virtual network connection look correct. Does the last step (static ip) effect the virtual connection?
Aaron - Not sure what you mean by "nothing on the guest." Based on your description, your host should have a valid dynamic IP address on the new virtual LAN connection. Make sure this is so and that the host has network connectivity.
After that, you'll need to IP your guest to be on the same network.
Boy Am I glad that I found your Blog. I've been spending almost 3 days in trying to make this Virtual Network "Working". FInally, It's working. I follow your procedure and, and, and something important I've disable IP Version 6 everywhere.
Thank's thank' a lot.
I'm "Happy" again now and moving forward with Hyper-V (RCO).
I am trying to assign sttic IPs to virtual machines using C#, I am able to create the machines with network cards using the WMI virtualization class libraries. Do you have any ideas to what API i can use to change the IPs?
Thanks man, good stuff. It felt more complex than it was. You def helped to understand it.
I'm trying to get Hyper-V configured on a server with 2 physical NICs; one dedicated to use for the host server and the other purely for virtual servers.
However, I keep losing connectivity. How should the virtual NIC on the host be configured for IP settings?
You rock! I've been having problems with Client for Microsoft Networks not binding and this helped out a whole bunch!
I blew away my virtual NIC that couldn't bind the CMN proto in Hyper-V manager and un-bound all the protocols on the physical NIC and re-created it and viola! I have a virtual NIC that can bind to the CMN protocol.
Jeff, you rock!
> I have a virtual NIC that can bind to the CMN protocol.
Could it be that before you had IPv6 disabled, and now it is enabled? I found that since installing Hyper-V, Client for Microsoft Network refuses to be enabled unless IPv6 is also enabled. Seems to be a bug to me. Even now with IPv6 I can enable it, but can't set the name service provider in the drop-down.
Still having RPC problems...
excellent work! this did it for me :)
mike
Jeff,
I just found your blog site here.
I have a question here -
After all Vitural Switch and Virtual NIC setup through Virtual Network manager, and one virtual machine adds this Virtual NIC as its own network adapter (of course it uses virtual network driver), how do you plan to configure IP in the virtual machine?
In my testing, it seems virtual machine can assign a different IP to this network adapter (actually it is Virtual NIC from host's standpoint) from the IP assigned to this Virtual NIC from host.
If DHCP exists, it looks different dynamic IPs will be assigned to this Virtual NIC, from Host and this virtual machine standpoint.
I'm not sure I follow you.
When you install Hyper-V, both the host AND the guest(s) use a virtual NIC. Each NIC will have its own IP address, either static or dynamic based on the IP configuration.
I was having the same problem as anonymous after following your steps. It still would not open stuff through a unc network path. With IPv6 off I could not keep Windows Network Client on, and I could not define an RPC locater. Finally after much trial and error I found a fix that is a bit strange. When I bridged my physical host network adapter with my virtual network adapter everything started working. Now I know it does this already when you create a virtual network...but when I did it on the host through the network connections pages everything started working....?!?!
I might be missing something in my search but I am trying to add a second NIC to the guest os. I don't see any ability to add a second network device to the Guest.
To add a second NIC to a Hyper-V guest, shutdown the guest and open the guest's Settings. Then select Add Hardware and add either a Network Adapter or a Legacy Network Adapter.
Ignore my last message. I figured out that with Hyper-V you first need to create a snapshot then you can add new hardware devices to the quest
All you said is true, but the problem I am having is that after updates are install the Virtual Machine Network Adapter does not appear under the device manager. And hence there is no connectivity on the Virtual Machine... Any ideas..
David
David, you can always connect to a Hyper-V guest from the Hyper-V console in Server Manager, even if networking is not working or installed.
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