Troubleshooting Virtual Network Switch in Windows Server 2012

Posted on 2013-10-02
Medium Priority
Last Modified: 2013-12-01
Configuring my first Server 2012 installation. Created VM in hypervisor.

Server is whitebox. 1 onboard Intel Nic and 1 add-on Intel Nic.

Setup Network Switch as External.

I am just trying to get network connectivity in the vm so that I can do updates and install software and do testing. I haven't assigned Static IP Addresses or anything yet.
Question by:MJCS
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Expert Comment

by:Cliff Galiher
ID: 39541534
I suspect you are having VLAN issues and therefore the traffic is not getting out as expected. VLAN support requires a quality business NIC, and my experience is that the basic Intel adapters usually don't support the way Hyper-V pre-tags the network traffic from the VMs.


Author Comment

ID: 39544408
So like a dual-port such as Intel ET Series Dual Port Gigabit Desktop Network Adapter, PCI-E?
LVL 61

Accepted Solution

Cliff Galiher earned 2000 total points
ID: 39544460
In general, I don't recommend any of Intel's "desktop adapter" series for Hyper-V hosting production server VMs (or VMs planned for eventual production use.)  The name says it all. Desktop adapters are for desktop machines. Lighter use, heavier reliance on the CPU and bridge. Server adapters are just better suited for Hyper-V, and especially at volumes of traffic that get pushed through the virtual switch (or even the adapter supporting pre-tagged VLAN packets), you get a better experience with server adapters.

Now with that said, if your VLAN configuration is not set up properly, no adapter will help. I can't help but notice your "management" VLAN ID was 1, and 1 is usually "special" on network equipment that supports VLANs at all. Usually not a good idea to actively tag packets with that VLAN ID. Either leave them untagged and let the equipment internally manage VLAN 1, or use a different VLAN ID.

Secondly for all the screengrabs you posted, none included the VM VLAN configuration. If you didn't set that up, of course you will have problems, even with the best adapter in the world.  Not to mention that even if you did include a screen shot of your VM's VLAN setup, it wouldn't guarantee that the switch, router, whatever is providing DHCP, and other equipment is also configured for the VLAN that the VM is on. You can't expect it to get internet access if it is on a VLAN alone and the switch and router can't access that VLAN.

Anyways, as you can see, there are a lot of moving parts, and the screen shots you provided gave me *just* enough of a peak to be fairly confident that this is the issue, not the Hyper-V virtual switch. But without digging into the entire network in much greater detail,  I can't give you more advice than what I already have.

1) Use a server adapter.
2) Verify your VLAN traffic, which is mostly unrelated to Hyper-V, and make sure traffic is even flowing in that regard as you designed or expected.


Author Comment

ID: 39580535
I deleted all of the virtual switches. Then I recreated and it worked, but later it broke again.

I bought an Intel Dual-Port Server Adapter. It seems much less finicky. I haven't had any issues since I got it.

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