HyperV Guests lose network connection

D

danman

[H]ard|Gawd
Joined
Aug 17, 2005
Messages
1,668
I have an ongoing issue with my 2008 R2 server. If I power it down (so its off) and then power it back up, all my VM’s cannot connect to the network. On the host I see that the HyperV NIC shows up in the network connections as a public network and says no internet connection. I have to delete this connection in the HyperV network setting and then recreate it. After that I have to re-bind the NIC to all guests.

This happens with the built in Intel Pro1000 NICs as well as a Broadcom dual port NIC. If I just reboot the server then everything is fine. Anyone ever seen this before? Is there a patch for this?
 
I had something similar happen on a Hyper-V Windows 2008 server that had DNS (read-only backup DNS for my house, primary DNS was housed in a virtual DC running on the same server) bound to the interface on the production network.

I had to disable and enable the physical NIC the virtual NIC was actually using after every reboot to get network connectivity back through the virtual NIC. I just set up a batch file to do this automatically 5 minutes after boot completed using a scheduled task and netsh.

Problem went away when I did an in place upgrade to Windows 2008 R2. Haven't had any similar issues with the new 2008 R2 server I built to replace the old one.
 
what type of hardware are you seeing this on? I under stand which NIC's but is the server an HP or a Dell? (or other). I have seen this same thing on 3 of my larger VM hosts but always only on the HP's.
 
No, it's an Intel S3420GPX board with a Xeon proc. Both Intel NIC's are enabled but not bound to HyperV. When I had one Intel NIC used as a HyperV NIC I had the problem. I added in a dual port Broadcom NIC and still have the problem (Put the Broadcom in to dedicate to HyperV hosts). I noticed that it only happens when there is no power, if I leave the power connected but the server off everything is fine. If I remove the power (like I did today to put in 16GB of RAM) the issue crept up.
 
thanks for the info. no current patch that i know of, but it is something i will ask about in SP1. there are alot of hyper-v and server OS fixes in SP1.
 
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