The answer is to deploy a NAT gateway in a public subnet and update the private subnets’ route table to point default traffic (0.0.0.0/0) to the NAT gateway. This is the most secure way to provide outbound internet access to private subnets because the NAT gateway allows instances to initiate outbound connections for tasks like software updates, but it drops any unsolicited inbound traffic from the internet, effectively acting as a one-way door. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this question tests your understanding of how to combine network address translation with route tables to enforce a security boundary—a core concept for designing resilient, multi-AZ VPC architectures. A common trap is confusing a NAT gateway with an internet gateway attached directly to private subnets, which would expose those workloads to inbound attacks. Remember the memory tip: NAT is a “no-answer translator”—it lets you talk out but never listens in.
ANS-C01 Network Implementation Practice Question
This ANS-C01 practice question tests your understanding of network implementation. 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 is deploying a VPC with public and private subnets in two Availability Zones. The workloads in the private subnets need to access the internet for software updates. What is the MOST secure way to provide this internet access?
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 update the private subnets' route table to point default traffic to the NAT gateway.
Using a NATgateway in a public subnet is the most secure approach because it allows outbound traffic while preventing inbound connections from the internet. Option A is wrong because an internet gateway attached to private subnets would expose them directly. Option C is wrong because a transit gateway is for connecting multiple VPCs, not providing internet access. Option D is wrong because a VPN connection is for private connectivity, not internet access.
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.
✓
Deploy a NAT gateway in a public subnet and update the private subnets' route table to point default traffic to the NAT gateway.
Why this is correct
NATgateway allows outbound internet access while blocking unsolicited inbound traffic.
Set up a VPN connection to an on-premises network with internet access.
Why it's wrong here
VPN provides private connectivity, not internet access for the VPC.
✗
Use a transit gateway with a VPC attachment and route internet traffic through a centralized inspection VPC.
Why it's wrong here
Transit gateway is for inter-VPC routing, not directly for internet access.
✗
Attach an internet gateway to the VPC and route the private subnets' traffic to it.
Why it's wrong here
This would make the private subnets directly accessible from the internet, reducing security.
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 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.
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 Implementation — This question tests Network Implementation — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Deploy a NAT gateway in a public subnet and update the private subnets' route table to point default traffic to the NAT gateway. — Using a NAT gateway in a public subnet is the most secure approach because it allows outbound traffic while preventing inbound connections from the internet. Option A is wrong because an internet gateway attached to private subnets would expose them directly. Option C is wrong because a transit gateway is for connecting multiple VPCs, not providing internet access. Option D is wrong because a VPN connection is for private connectivity, not internet access.
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 is deploying a VPC with public and private subnets in two Availability Zones. They need to ensure that instances in private subnets can access the internet for software updates while remaining unreachable from the internet. Which solution meets these requirements?
easy
A.Attach an internet gateway to the private subnets and configure route tables.
✓ B.Deploy a NAT Gateway in a public subnet and add a route to the NAT Gateway in the private subnet route tables.
C.Use a transit gateway to connect the VPC to the internet.
D.Establish a VPN connection to an on-premises network and route traffic through it.
Why B: Option B is correct because a NAT Gateway deployed in a public subnet provides outbound-only internet access for instances in private subnets. The private subnet route table directs 0.0.0.0/0 traffic to the NAT Gateway, which translates the private IPs to the NAT Gateway's Elastic IP, allowing internet access while preventing any unsolicited inbound connections from the internet.
Variation 2. A company is deploying a VPC with public and private subnets in two Availability Zones. The public subnets host NAT gateways for outbound internet access from the private subnets. Which configuration ensures that EC2 instances in the private subnets can route traffic to the internet through the NAT gateways?
easy
A.Add a route in the public subnet route table pointing to the internet gateway.
B.Attach an egress-only internet gateway to the private subnets.
C.Create a VPC peering connection between the VPC and the NAT gateway.
✓ D.Add a route in the private subnet route table with destination 0.0.0.0/0 targeting the NAT gateway.
Why D: Option B is correct because the private subnet route table must have a default route (0.0.0.0/0) pointing to the NAT gateway to allow outbound internet traffic. Option A is wrong because internet gateway is for public subnets. Option C is wrong because VPC peering doesn't provide internet access. Option D is wrong because egress-only internet gateways are for IPv6.
Variation 3. A company is deploying a VPC with public and private subnets in two Availability Zones. The private subnets need outbound internet access for software updates but must not be reachable from the internet. Which AWS service should be used to achieve this?
medium
A.VPC Peering
B.Virtual Private Gateway
✓ C.NAT Gateway
D.Internet Gateway
Why C: A NAT Gateway allows instances in private subnets to initiate outbound traffic to the internet while preventing inbound traffic from the internet.
Last reviewed: Jun 20, 2026
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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.
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