Question 375 of 1,546
Networking and Content DeliveryhardMultiple ChoiceObjective-mapped

Quick Answer

The answer is AWS PrivateLink, which is the correct choice because it enables private IP communication between VPCs with overlapping CIDRs by using VPC endpoints and a Network Load Balancer, avoiding the route conflicts that would break Transit Gateway. Since VPC A and VPC B share the same 10.0.0.0/16 block, Transit Gateway cannot distinguish traffic between them, but PrivateLink bypasses this by allowing VPC A and VPC B to initiate connections to services hosted in VPC C without requiring direct IP routing or route table entries between the VPCs. On the AWS Certified SysOps Administrator Associate SOA-C02 exam, this scenario tests your understanding of how to handle overlapping CIDRs when connecting multiple VPCs—a common trap is choosing Transit Gateway because it’s a popular hub-and-spoke solution, but it fails here due to route table ambiguity. Remember the memory tip: “Overlap? PrivateLink’s your link—no routes, no conflicts.”

SOA-C02 Networking and Content Delivery Practice Question

This SOA-C02 practice question tests your understanding of networking and content delivery. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A company has three VPCs in the same AWS region: VPC A (production), VPC B (development), and VPC C (shared services). The VPCs have overlapping CIDR blocks (e.g., VPC A: 10.0.0.0/16, VPC B: 10.0.0.0/16, VPC C: 10.1.0.0/16). The SysOps administrator needs to enable private IP communication between VPC A and VPC C, and between VPC B and VPC C, but not between VPC A and VPC B. The solution must also support a growing number of VPCs in the future. Which AWS service should be used?

Question 1hardmultiple choice
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Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Use AWS PrivateLink by creating a Network Load Balancer in VPC C and configuring VPC endpoints in VPC A and VPC B to access the services.

AWS Transit Gateway (Option A) cannot be used because the VPCs have overlapping CIDR blocks (10.0.0.0/16 for both VPC A and VPC B), which prevents Transit Gateway from routing traffic correctly due to route conflicts. AWS PrivateLink (Option B) solves this by allowing VPC A and VPC B to access services in VPC C via VPC endpoints and a Network Load Balancer, without requiring direct IP routing between the VPCs, thus avoiding CIDR overlap issues and supporting future VPC growth.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Use AWS Transit Gateway with attachment route tables that isolate traffic between VPCs, ensuring that VPC A and VPC B routes are separate.

    Why it's wrong here

    Transit Gateway can segregate traffic using separate route tables, but overlapping CIDR blocks (VPC A and VPC B both have 10.0.0.0/16) cause routing ambiguity. While the route tables can prevent direct communication, traffic destined to VPC C (unique CIDR) works, but the overlapping issue complicates routing and may lead to unpredictable behavior. Transit Gateway is not recommended for overlapping CIDRs.

  • Use AWS PrivateLink by creating a Network Load Balancer in VPC C and configuring VPC endpoints in VPC A and VPC B to access the services.

    Why this is correct

    AWS PrivateLink allows you to expose services in VPC C via a Network Load Balancer, and VPC A and VPC B can create interface VPC endpoints to connect to those services privately. This works even with overlapping CIDRs because the endpoints are assigned specific private IP addresses from the VPC's subnet and traffic is directed using endpoint-specific routing. It also scales well with additional VPCs.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Create two VPC peering connections: one between VPC A and VPC C, and one between VPC B and VPC C.

    Why it's wrong here

    VPC peering does not support overlapping CIDR blocks. If VPC A and VPC B both have CIDR 10.0.0.0/16, they cannot peer with VPC C if VPC C's CIDR also overlaps? VPC C is 10.1.0.0/16, no overlap. The peering between VPC A and VPC C would work, but VPC A's route table would need a route to VPC C (10.1.0.0/16) via the peering connection. However, if VPC A has a subnet 10.0.0.0/24, and VPC B has a subnet 10.0.1.0/24, traffic from VPC A to 10.0.1.0/24 would be sent to the peering connection if a route exists, but that's only for VPC C? This is messy. VPC peering requires non-overlapping CIDRs to function correctly because if VPC A has 10.0.0.0/16 and tries to reach 10.0.1.0/24 (which is in VPC B, but they are not peered), it will route locally. But with VPC C, peering is fine. However, VPC peering does not scale well for many VPCs as it requires full mesh or hub-and-spoke. This option is valid but less scalable and may have issues if future VPCs have overlapping CIDRs.

  • Set up two AWS Site-to-Site VPN connections from VPC C to VPC A and VPC B using virtual private gateways.

    Why it's wrong here

    Site-to-Site VPN is designed for connecting on-premises networks to AWS, not for VPC-to-VPC connectivity. While it could technically work, it is not optimal for within-region VPC connectivity due to higher latency, cost, and complexity. Also, overlapping CIDRs still cause routing issues.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates assume Transit Gateway or VPC peering can handle overlapping CIDRs through route table isolation, but AWS explicitly requires non-overlapping CIDRs for both services to function correctly, making PrivateLink the only viable option for this scenario.

Detailed technical explanation

How to think about this question

AWS PrivateLink uses VPC endpoints (interface or Gateway Load Balancer endpoints) to privately connect VPCs to services hosted on a Network Load Balancer (NLB) in another VPC, without requiring VPC peering or transit routing. The NLB in VPC C handles traffic from VPC A and VPC B via separate endpoint connections, and because PrivateLink operates at the application layer (via DNS and ENIs), it bypasses IP-level routing conflicts caused by overlapping CIDRs. This design also scales horizontally as new VPCs can be added by creating additional VPC endpoints, making it ideal for hub-and-spoke architectures with CIDR overlap.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Related practice questions

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FAQ

Questions learners often ask

What does this SOA-C02 question test?

Networking and Content Delivery — This question tests Networking and Content Delivery — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Use AWS PrivateLink by creating a Network Load Balancer in VPC C and configuring VPC endpoints in VPC A and VPC B to access the services. — AWS Transit Gateway (Option A) cannot be used because the VPCs have overlapping CIDR blocks (10.0.0.0/16 for both VPC A and VPC B), which prevents Transit Gateway from routing traffic correctly due to route conflicts. AWS PrivateLink (Option B) solves this by allowing VPC A and VPC B to access services in VPC C via VPC endpoints and a Network Load Balancer, without requiring direct IP routing between the VPCs, thus avoiding CIDR overlap issues and supporting future VPC growth.

What should I do if I get this SOA-C02 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 11, 2026

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This SOA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SOA-C02 exam.