I have two Windows 2016 VMs set up as an NLB cluster. Each guest has two interfaces, one of which is for the NLB, the other for other traffic.

I've added an IPv4 and an IPv6 address to the cluster. Both are set up to use IGMP multicast, with no affinity. Each has a separate mac address, and I've added these MACs to our core switch, as we use several hosts with VMotion.

IPv4 works fine from anywhere, but I am unable to access the IPv6 address. If I go into the cluster properties and change the cluster ip address under the cluster parameters tab to the IPv6 address, IPv4 stops working.

This leads me to suspect that dual-stack configuration of NLB is not supported, but requires a separate network adapter for each of IPv4 and IPv6.

What makes this all somewhat headscratching, is that ping6 works from one linux server on the same vlan, getting duplicate replies, as both guests reply. But from the router or a server on another vlan, ping of the ipv6 address fails.

Any insights on this would be greatly appreciated.


As far as I can see, Dual stack NLB is supported, but brings me (and you) to the following problem

For an IPv4 NLB in vmware you have to set the cluster operation mode in and create an ARP entry on the first switch for this IPv4 and virtual MAC address

(for cisco that would be something as : arp 03bf.0000.0000 ARPA)

IPv6 doesnot use ARP, so you cannot create an ARP entry on the switch. my conclusion would be that you have to set the cluster operation mode in , Which seems to work.

Problem for me is that you cannot create a NLB interface with for IPv4 and for IPv6

An extra (for me) weird result is that when I place the cluster operation mode in I can ping the IPv6 address from another computer (which is physical connected to the same switch) but not from the switch itself

So I don’t have a complete answer, only more insight of the problem If you found the answer, please share this with the world ;)

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