Microsoft NLB not working properly in Unicast Mode (1556)
kb.vmware.com › s › articleFeb 22, 2017 · When running Microsoft Network Load Balancing (NLB) configured in unicast mode, the Network traffic is directed to only one of the nodes. Solution In unicast mode, all the NICs assigned to a Microsoft NLB cluster share a common MAC address. This requires that all the network traffic on the switches be port-flooded to all the NLB nodes.