An NC2 on Azure environment requires that outside networks are allowed to be routed to a Nutanix User VPC from outside the cluster when using a…

For No-NAT connectivity, traffic from external networks is routed directly to the workload NIC address inside the Nutanix User VPC. Nutanix therefore requires the User VPC to use an IP prefix that is globally or enterprise-wide routable and advertised outside the cluster. The external network must share—that is, use routes that point to—the same address space as the Nutanix User VPC; Azure native subnets are irrelevant because No-NAT bypasses Azure’s NAT translation. Consequently, the environment must assign an externally routable IP block to the User VPC, satisfying option D.

A. Internally routable addresses cannot be reached from external networks.

B. Sharing Azure native subnet space creates overlap and routing ambiguity.

C. Internal (RFC1918) ranges inside Azure are not externally routable without NAT.

1. Nutanix NC2 on Azure Networking Guide, §6.2 “No-NAT VPC Requirements” (“Use an externally routable prefix identical to the User VPC address space”).

2. Nutanix Field Advisory FA-2271, “Routing external networks to NC2 User VPC (No-NAT)”, para 2-3.