====== NIOS on Nutanix ======
If customer had deployed NIOS on Nutanix and has IPv6 enabled, if they have MLD/IGMP snooping enabled on Nutanix but no RP/multicast configuration on their router (and the vSwitch was in passthrough), then the deployment would cause ND/RA to fail after a few minutes.
 
Note that in VMware, a vSwitch runs in "Basic" mode (passthrough), and a Distributed vSwitch can be configured to run in "Basic" or "IGMP/MLD snooping" mode. You may need to return "Basic" mode to get IPv6 to function consistently after upgrade to NIOS 9. This is because NIOS implemented interactions with multicast protocols due to the underlying OS upgrade.
 
If the Nutanix AHV is running IGMP (and MLD) and they don't have the router upstream provisioned correctly, the switches won't run the multicast groups correctly and multicast joins will fail (and thus we stop sending and receiving multicasts). This breaks IPv6, since neighbor and router discovery is all done via multicast. If the Nutanix AHV isn't running IGMP/MLD and the upstream switch is, it's possible there may still be issues.
 
With IPv6, whenever it "works for a little bit then stops" (about 5 minutes, unless constantly pinged), after a reboot or restart of networking, that's going to be a multicast issue on the underlying network.