I'm going to describe the issue as best as I can, but it's extremely odd to say the least...
We have 2 new servers, HP DL380 G7s. that are going to be the start of a new Hyper-V cluster. I built the first one up with minimum fuss, but the second has NIC issues as soon as I add the Hyper-V role.
From the four on-board NICs, two are in our domain VLAN 1, and the other 2 in their own VLAN 18. They will be teamed, but for the sake of simplicity I'll keep teaming out of this for now. Before adding the Hyper-V role I can ping out of every single NIC, after adding the Hyper-V role 1 of the NICs no longer respond to ping.
At this point I have not created any virtual NICs, nor changed anything in the physical NIC adapter settings
I remove the Hyper-V role and they all start to work again, I re-add the role and a different NIC stop working.
The driver and firmware versions are exactly the same as the server that currently works. Also, NICs 1+3 go to one of our DC switches, and 2+4 go to another, this is to add redundancy once they get teamed. However for testing I have now patched in the problematic server directly into the same ports the working server was using.
To add to the strangeness, if I create a virtual switch using the NIC that doesn't work I can then ping out of that.
Any ideas welcome :-)
Andrew France - http://andrewsprivatecloud.wordpress.com