I'm dealing with the following situation: I have 2 servers running Windows 2012 R2 and 1 server running Windows 2008 R2. I need to build a Microsoft Network LoadBalancer cluster using the 3 servers; servers are connected to a cisco Nexus Switch; servers are using Intel as well as Broadcom Nic cards. The servers are in the same subnet and the Network LoadBalancer VIP of the newly formed cluster is also in the same subnet. As long as wireshark is running on the servers the cluster is working (setting the nic interfaces to promiscuous mode) - members are detecting / seeing each other and passing each other the Primary / Master role when configured via the Network Load Balancer UI. How can this be possible?
Another strange thing: if I take one of the member offline from the cluster and run a Wireshark capture, I can see the Microsoft Network Load Balancer heartbeat broadcast messages being received from that host; nevertheless, as soon as I add the host again in the cluster, and I restart Wireshark, then the Network Load balancer cluster is working but in the Wireshark capture, I don't see any Network Load Balancer hearthbeat messages received any longer.
Moreover, each time I take any host offline from the Network Load Balancer cluster or add it to the Network Load Balancer cluster, Wireshark stops the formerly ongoing capture and displays a notification message stating that the ongoing capture cannot continue as the NIC formerly in use is no longer available.