The answer is a NAT Gateway in a public subnet paired with a private route table that routes 0.0.0.0/0 traffic to that NAT Gateway. This design works because the NAT Gateway, residing in a public subnet with an Internet Gateway, translates private IPs to its own Elastic IP for outbound traffic, while the private subnet’s route table ensures return traffic flows back through the NAT Gateway, preventing any direct inbound connections. On the AWS Certified SysOps Administrator Associate SOA-C02 exam, this scenario tests your understanding of how to provide private subnet internet access using NAT Gateway design without exposing resources—a common trap is confusing a NAT Gateway with an Internet Gateway, which would make the subnet public. Remember the key distinction: an Internet Gateway enables bidirectional access, while a NAT Gateway only allows outbound-initiated traffic. For a quick memory tip, think “NAT in public, route in private” to keep the architecture straight.
SOA-C02 Networking and Content Delivery Practice Question
This SOA-C02 practice question tests your understanding of networking and content delivery. 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 designing a VPC with public and private subnets. The private subnets need internet access for patching, but must not be directly reachable from the internet. Which TWO components should be used together?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Private subnet route table with a route to the NAT Gateway
Option A (NATGateway) and Option D (Private route table with route to NAT) are correct. A NAT Gateway in a public subnet provides outbound internet access, and a private route table directs traffic to the NAT Gateway. Option B is wrong because Internet Gateway is for public subnets. Option C is wrong because VPC Peering is for connecting VPCs, not internet access. Option E is wrong because a direct route to IGW would make the subnet public.
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.
✗
VPC Peering connection
Why it's wrong here
VPC Peering does not provide internet access.
✗
Private subnet route table with a route to the Internet Gateway
Why it's wrong here
This would make the subnet public.
✗
Internet Gateway attached to the VPC
Why it's wrong here
Internet Gateway alone makes subnets public if routes exist.
✓
Private subnet route table with a route to the NAT Gateway
Why this is correct
This route directs traffic from private subnets to the NATGateway.
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 SOA-C02 subnetting questions on CIDR, address ranges, and subnet selection.
Networking and Content Delivery — This question tests Networking and Content Delivery — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Private subnet route table with a route to the NAT Gateway — Option A (NAT Gateway) and Option D (Private route table with route to NAT) are correct. A NAT Gateway in a public subnet provides outbound internet access, and a private route table directs traffic to the NAT Gateway. Option B is wrong because Internet Gateway is for public subnets. Option C is wrong because VPC Peering is for connecting VPCs, not internet access. Option E is wrong because a direct route to IGW would make the subnet public.
What should I do if I get this SOA-C02 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 SOA-C02 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
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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 an Internet Gateway and a NAT Gateway. They launch an EC2 instance in a private subnet. The instance needs to download updates from the internet, but the security team wants to prevent any inbound traffic from the internet. Which route table configuration is correct for the private subnet?
medium
A.10.0.0.0/16 -> local; 0.0.0.0/0 -> VPC Peering
B.0.0.0.0/0 -> Internet Gateway
✓ C.0.0.0.0/0 -> NAT Gateway
D.No default route; only local routes.
Why C: Option C is correct because the private subnet route table should have a default route (0.0.0.0/0) pointing to the NAT Gateway for outbound traffic, and no route to the Internet Gateway. Option A is wrong because pointing to the Internet Gateway would allow inbound traffic. Option B is wrong because no route would block all traffic. Option D is wrong because directing to the VPC CIDR is for internal traffic.
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This SOA-C02 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 SOA-C02 exam.
Question Discussion
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