The answer is to create a Gateway VPC Endpoint for S3 and use it from the VPC. This solution is correct because a Gateway endpoint uses prefix lists and route table entries within the VPC’s own 10.0.0.0/16 range, allowing private access to S3 without traversing the Direct Connect private VIF or the overlapping on-premises 10.0.0.0/8 network. The overlapping CIDR with Direct Connect becomes irrelevant since S3 traffic stays entirely inside the VPC, avoiding any IP conflict. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this scenario tests your understanding of how VPC endpoints decouple traffic from Direct Connect routing, and a common trap is assuming a PrivateLink or Transit Gateway is needed when a simpler Gateway endpoint suffices for services like S3 and DynamoDB. Remember the memory tip: “Gateway endpoints stay local—no Direct Connect, no overlap.”
ANS-C01 Network Design Practice Question
This ANS-C01 practice question tests your understanding of network design. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 a VPC with a CIDR of 10.0.0.0/16 and uses AWS Direct Connect with a private VIF to connect to on-premises. The on-premises network uses 10.0.0.0/8. The company wants to access an AWS service (e.g., S3) privately from the VPC without using public endpoints. Which solution avoids IP overlap and meets the requirement?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create a VPC endpoint for S3 (Gateway type) and use it from the VPC.
Option B is correct because a Gateway VPC Endpoint for S3 allows private access to S3 from within the VPC without traversing the internet or requiring public IPs. It avoids IP overlap because the endpoint uses prefix lists and route table entries within the VPC's 10.0.0.0/16 range, and does not involve the on-premises 10.0.0.0/8 network. The Direct Connect private VIF is not used for S3 traffic, so the overlapping CIDR is irrelevant.
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.
✗
Create a NAT gateway in a public subnet and route S3 traffic through it.
Why it's wrong here
NATgateway is for internet access, not private access to S3.
✓
Create a VPC endpoint for S3 (Gateway type) and use it from the VPC.
Why this is correct
VPC endpoint provides private access without overlapping IPs.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use a public virtual interface and access S3 via public endpoints.
Why it's wrong here
Public VIF does not keep traffic within AWS network.
✗
Add a route in the VPC route table pointing to the Direct Connect virtual interface for the S3 prefix list.
Why it's wrong here
Overlapping CIDRs will cause routing conflicts.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume a private VIF can be used to reach AWS services privately, but they overlook the IP overlap between the VPC and on-premises networks, which breaks routing and makes Gateway VPC Endpoints the only viable solution.
Detailed technical explanation
How to think about this question
Gateway VPC Endpoints use a prefix list (e.g., com.amazonaws.region.s3) and add a route in the VPC route table pointing to the endpoint ID. Traffic destined for S3 is routed within AWS's network without leaving the VPC, and the endpoint scales automatically up to 10 Gbps per endpoint. A subtle behavior is that Gateway Endpoints do not support on-premises access via Direct Connect or VPN unless the on-premises network uses the endpoint's DNS names and routes through the VPC, which is not possible here due to the overlapping CIDR.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
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.
Network Design — This question tests Network Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create a VPC endpoint for S3 (Gateway type) and use it from the VPC. — Option B is correct because a Gateway VPC Endpoint for S3 allows private access to S3 from within the VPC without traversing the internet or requiring public IPs. It avoids IP overlap because the endpoint uses prefix lists and route table entries within the VPC's 10.0.0.0/16 range, and does not involve the on-premises 10.0.0.0/8 network. The Direct Connect private VIF is not used for S3 traffic, so the overlapping CIDR is irrelevant.
What should I do if I get this ANS-C01 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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.