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 solutions architect is designing a VPC with public and private subnets in two Availability Zones. The private subnets require outbound internet access for software updates, but inbound internet access must be blocked. Which solution meets these requirements?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Deploy a NAT Gateway in a public subnet and add a default route to the NAT Gateway in the private subnet route tables.
Option B is correct because a NATGateway, deployed in a public subnet with an Elastic IP and a route to an Internet Gateway, enables outbound traffic from private subnets to the internet while blocking unsolicited inbound connections. The private subnet route table directs default traffic (0.0.0.0/0) to the NAT Gateway, which performs source network address translation (SNAT) on outbound packets, ensuring responses return to the NAT Gateway without exposing private instances directly.
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.
✗
Attach an internet gateway to the VPC and add a default route to the internet gateway in the private subnet route tables.
Why it's wrong here
This allows inbound traffic as well.
✓
Deploy a NAT Gateway in a public subnet and add a default route to the NAT Gateway in the private subnet route tables.
Why this is correct
NATGateway provides outbound-only internet access.
Related concept
Read the scenario before looking for a memorised answer.
✗
Launch an EC2 instance in a public subnet with a proxy software and route private subnet traffic through it.
Why it's wrong here
This is a valid but less optimal solution due to management overhead.
✗
Create a VPC endpoint for Amazon S3 and add a route to the endpoint in the private subnet route tables.
Why it's wrong here
VPC endpoints are for AWS services, not general internet.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse a NAT Gateway with an Internet Gateway, thinking that a default route to an Internet Gateway in a private subnet is acceptable, but an Internet Gateway allows bidirectional traffic, which would expose private instances to inbound internet connections.
Detailed technical explanation
How to think about this question
A NATGateway uses SNAT to translate private IP addresses to its Elastic IP address for outbound traffic, and it maintains connection state so that return traffic is correctly forwarded to the originating private instance. Unlike a NAT instance, a NAT Gateway is managed by AWS, automatically scales up to 45 Gbps, and does not require disabling source/destination check. In a real-world scenario, if software update repositories are hosted on the internet (e.g., yum repos, Windows Update), the NAT Gateway is the standard solution; for updates from AWS services like S3, a VPC Gateway Endpoint is more cost-effective and avoids NAT Gateway data processing charges.
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: Deploy a NAT Gateway in a public subnet and add a default route to the NAT Gateway in the private subnet route tables. — Option B is correct because a NAT Gateway, deployed in a public subnet with an Elastic IP and a route to an Internet Gateway, enables outbound traffic from private subnets to the internet while blocking unsolicited inbound connections. The private subnet route table directs default traffic (0.0.0.0/0) to the NAT Gateway, which performs source network address translation (SNAT) on outbound packets, ensuring responses return to the NAT Gateway without exposing private instances directly.
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.