NCP-CI-AZURE practice question 1 of 10

The cluster has the following configuration: A Transit VPC exists as Default, but is additionally configured with a overlay-external-subnet-nonat…

The cluster has the following configuration: A Transit VPC exists as Default, but is additionally configured with a overlay-external-subnet-nonat overlay subnet The ERP for the Transit VPC is 10.1.1.0/25 A User VPC exists named User_VPC_Prod The ERP for the User VPC is 10.1.1.0/24 Outbound and inbound routes have been configured A User VM NO-NAT subnet has been configured in the User VPC The administrator has successfully created a VM and added the NIC associated with the NO-NAT subnet, but is not able to communication with other resources. Which option will resolve this issue?

Answer options

A: The ERP in the User VPC must be from a different CIDR range than the ERP in the transit VPC. Correct answer

B: Ensure that the security groups associated with the VM allow traffic to and from the desired resources.

C: Verify that the route table associated with the User VPC has appropriate routes to the Transit VPC.

D: Check that the network ACLs for the NO-NAT subnet are not blocking the necessary traffic.

Correct Answer:

A. The ERP in the User VPC must be from a different CIDR range than the ERP in the transit VPC.

Explanation

NC2 requires every VPC’s External Routed Prefix (ERP) to be unique and non-overlapping. In the scenario, the UserVPC ERP (10.1.1.0/24) fully overlaps the Transit VPC ERP (10.1.1.0/25). Because the routing table cannot contain two identical or overlapping prefixes, packets addressed to the NO-NAT subnet are dropped, preventing communication. Changing the User VPC ERP to a CIDR block that does not intersect with the Transit VPC’s ERP eliminates the conflict and restores reachability.

Why Incorrect

B. Security groups cannot fix overlapping CIDRs; routing conflict remains.
C. Routes cannot be established while prefixes overlap; conflict must be removed first.
D. ACLs are evaluated after routing; overlap prevents packets from reaching ACL stage.

References

1. NC2 on Azure Networking Guide v6, §5.3 “External Routed Prefix Rules” (“Each VPC must use a unique, non-overlapping ERP”).

2. Nutanix Cloud Clusters on Azure Troubleshooting KB-8812, “Communication failure due to overlapping ERP”, Steps 1-3.

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