The answer is a NAT gateway in a public subnet. This is correct because a NAT gateway enables instances in private subnets to initiate outbound traffic to the internet for tasks like software updates, while preventing any unsolicited inbound connections—a process known as source network address translation (SNAT). On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this concept tests your understanding of how to architect secure outbound connectivity without assigning public IP addresses, often appearing in scenario-based questions that contrast NAT gateways with internet gateways, which require public IPs, or VPC endpoints, which only access AWS services. A common trap is confusing a NAT gateway with an internet gateway; remember that an internet gateway alone cannot provide NAT for private instances. Memory tip: “NAT in the public, private stays quiet”—the gateway lives in the public subnet to translate private IPs for outbound internet access.
ANS-C01 Network Security, Compliance and Governance Practice Question
This ANS-C01 practice question tests your understanding of network security, compliance and governance. 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 public and private subnets. The private subnets need to access the internet for software updates. Which AWS service should be used to provide internet access to instances in the private subnets without assigning public IP addresses?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
NAT gateway in a public subnet.
Option A is correct because a NATgateway allows instances in private subnets to initiate outbound traffic to the internet. Option B is wrong because Internet Gateway alone does not provide NAT; it requires public IPs. Option C is wrong because VPN does not provide direct internet access. Option D is wrong because VPC endpoint is for accessing AWS services.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
NAT gateway in a public subnet.
Why this is correct
NATgateway enables outbound internet access for private instances.
Internet gateway requires instances to have public IPs; private instances don't have them.
✗
VPC Gateway Endpoint for Amazon S3.
Why it's wrong here
Gateway Endpoint only provides access to S3 and DynamoDB, not general internet.
✗
Site-to-Site VPN connection.
Why it's wrong here
VPN connects to on-premises, not directly to internet.
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
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.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related ANS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
Network Security, Compliance and Governance — This question tests Network Security, Compliance and Governance — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: NAT gateway in a public subnet. — Option A is correct because a NAT gateway allows instances in private subnets to initiate outbound traffic to the internet. Option B is wrong because Internet Gateway alone does not provide NAT; it requires public IPs. Option C is wrong because VPN does not provide direct internet access. Option D is wrong because VPC endpoint is for accessing AWS services.
What should I do if I get this ANS-C01 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related ANS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company has a VPC with public and private subnets. The security team wants to allow instances in a private subnet to download software updates from the internet but prevent inbound internet traffic. Which AWS service should be used?
easy
A.Internet gateway
B.AWS Site-to-Site VPN
C.VPC peering connection
✓ D.NAT gateway
Why D: A NAT gateway allows outbound internet traffic from private subnets while blocking unsolicited inbound traffic. Option C is correct. Option A is wrong because internet gateway allows bidirectional traffic. Option B is wrong because VPC peering is for VPC-to-VPC. Option D is wrong because VPN is for hybrid connectivity.
Last reviewed: Jun 20, 2026
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.
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.