I have two instances of Windows Server 2008 running in Hyper-V VM's. The two instances are configured in a multicast NLB. I can ping either node from another subnet, but I get a timeout when pinging the NLB name.
If I stop NLB on one node and take a network trace on the remaining node, I see that an ARP request for the NLB's IP address gets to the VM... but the VM never sends an ARP reply.
Can anyone suggests causes and solutions? There are many articles out there about the router not forwarding ARP requests to NLB nodes, but that doesn't appear to be the problem here, as the NLB nodes do get the ARP request; they just don't respond.
EDITS: MAC address spoofing is enabled on both nodes in Hyper-V manager.