Doubt on correct answer regarding VPC

[TJ Contreras]

Hi TD team, I’m learning a lot in these practice exams and it helped to prepare more. However, I stumbled in this question and I was skeptic on the answer and explanation provided. Could you help me out on this?

The question is:

A company has multiple VPCs with IPv6 enabled for its suite of web applications. The Solutions Architect attempted to deploy a new Amazon EC2 instance but encountered an error indicating that there were no available IP addresses on the subnet. The VPC has a combination of IPv4 and IPv6 CIDR blocks, but the IPv4 CIDR blocks are nearing exhaustion. The architect needs a solution that will resolve this issue while allowing future scalability.

How should the Solutions Architect resolve this problem?

The correct answer is: Set up a new IPv4 subnet with a larger CIDR range. Associate the new subnet with the VPC and then launch the instance.

I have doubt in this answer because it doesn’t address the problem of the “IPv4 CIDR blocks are nearing exhaustion” and the issue about “future scalability”. How would creating a new subnet with a larger CIDR range solves the issue if the IPv4 CIDR block are nearing in the exhaustion in the first place? Do you mean to create a new secondary IPv4 CIDR Block in the VPC?

Thanks in advance and more powers to TD team. 🙂

[Irene-TutorialsDojo]

Hi TJ Contreras,

Thank you for reaching out with your question. We understand your concern about the initial explanation. You are correct that creating a new IPv4 subnet doesn’t truly solve the problem of IPv4 exhaustion or address future scalability. We apologize for the confusion. The correct solution, which aligns with the problem’s details, is to leverage the company’s existing IPv6-enabled infrastructure.

The correct answer is indeed Option 3: Set up a new IPv6-only subnet with a large CIDR range. Associate the new subnet with the VPC, then launch the instance. This is the most effective solution because it bypasses the IPv4 exhaustion issue entirely. By creating a subnet that only uses IPv6, you can deploy new resources without consuming any of the limited IPv4 addresses, providing a vast, scalable address space for future growth.

We have updated the answer, and the update will be live on the portal shortly.

If you have further questions, don’t hesitate to ask.

Best,

Irene @ Tutorials Dojo