ANS-C01 Network Design Practice Question
A company is designing a network for a multi-account architecture using AWS Resource Access Manager (RAM) to share VPC subnets across accounts. They want to ensure that instances in shared subnets can communicate with instances in the owner's VPC using private IP addresses. What is required?
⚠ Common exam trap
The trap here is that candidates mistakenly think cross-account subnet sharing requires additional connectivity like VPC peering or a transit gateway, when in fact the shared subnet is logically part of the same VPC, so no extra networking is needed for private IP communication.
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
✓
No additional networking configuration is required; the shared subnet is part of the same VPC.
When you share a subnet using AWS Resource Access Manager (RAM), the shared subnet is part of the owner's VPC. Instances launched into that shared subnet reside in the same VPC as the owner's instances, so they can communicate using private IP addresses by default, with no additional networking configuration required. This is because VPC subnets are a logical subdivision of the VPC's CIDR block, and all instances within the same VPC can route to each other via the VPC's internal router.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Establish a VPC peering connection between the owner and participant accounts.
Why it's wrong here
Not needed; they are in the same VPC.
- ✗
Configure a VPC endpoint for Amazon EC2 to allow cross-account private communication.
Why it's wrong here
Not needed for same VPC communication.
- ✓
No additional networking configuration is required; the shared subnet is part of the same VPC.
Why this is correct
Shared subnets are within the same VPC, so routing is inherent.
- ✗
Create a transit gateway and attach both VPCs to it.
Why it's wrong here
They are in the same VPC, no transit gateway needed.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 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 ANS-C01 exam.