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ANS-C01: Expanding AWS VPC IP Address Space by Attaching Additional Private CIDR Blocks

Learn how to resolve depleted IP addresses in a VPC by safely attaching non-overlapping additional private CIDR blocks like 10.0.0.0/16 according to AWS networking rules.

Table of Contents

Question

A company’s application team is unable to launch new resources into its VPC. A network engineer discovers that the VPC has run out of usable IP addresses. The VPC CIDR block is 172.16.0.0/16.

Which additional CIDR block can the network engineer attach to the VPC?

A. 172.17.0.0/29
B. 10.0.0.0/16
C. 172.17.0.0/16
D. 192.168.0.0/16

Answer

B. 10.0.0.0/16

Explanation

The additional CIDR block that can be attached to the VPC is B:

10.0.0.0/16

The key points:

  • VPCs can have up to 5 CIDR blocks attached
  • CIDR blocks must not overlap
  • Private IP address ranges include 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16

The other options violate these rules:

A – Overlaps with existing 172.16.0.0/16 range
C – Same subnet as existing range
D – Private range but overlaps existing range

Only 10.0.0.0/16 satisfies the non-overlapping criteria as it is a standard private IP range that does not collide with the current VPC CIDR.

Attaching an additional 10.0.0.0/16 block is the ideal solution to expand the VPC IP address pool without conflicts.

AWS Certified Advanced Networking – Specialty ANS-C01 certification exam practice question and answer (Q&A) dump with detail explanation and reference available free, helpful to pass the AWS Certified Advanced Networking – Specialty ANS-C01 exam and earn AWS Certified Advanced Networking – Specialty ANS-C01 certification.