The answer is to create a NAT gateway in a public subnet and add a route to it in the private subnet route table. This configuration is correct because a NAT gateway resides in a public subnet with an Elastic IP, enabling instances in private subnets to initiate outbound internet traffic for tasks like software updates while completely blocking any unsolicited inbound connections from the internet. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of how to securely bridge private resources to the internet without exposing them, often appearing as a direct question about RDS instances or similar workloads needing external patches. A common trap is confusing a NAT gateway with an internet gateway, which would expose the private subnet, or mistakenly thinking a VPC peering or VPN connection provides internet access. Remember the memory tip: NAT is for outbound only, like a one-way door; the gateway lives in the public zone, but the route lives in the private zone.
SCS-C02 Infrastructure Security Practice Question
This SCS-C02 practice question tests your understanding of infrastructure security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 sub host Amazon RDS instances. To allow the RDS instances to access the internet for software updates without exposing them to inbound internet traffic, what should be configured?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create a NAT gateway in a public subnet and add a route to the NAT gateway in the private subnet route table.
Option B is correct because a NATgateway allows outbound internet traffic from private subnets while blocking inbound. Option A is wrong because an internet gateway in a private subnet would expose the instance. Option C is wrong because VPC peering is for connecting VPCs, not internet access. Option D is wrong because a VPN does not provide 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.
✗
Use a VPN connection to an on-premises network that has internet access.
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 SCS-C02 subnetting questions on CIDR, address ranges, and subnet selection.
Infrastructure Security — This question tests Infrastructure Security — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Create a NAT gateway in a public subnet and add a route to the NAT gateway in the private subnet route table. — Option B is correct because a NAT gateway allows outbound internet traffic from private subnets while blocking inbound. Option A is wrong because an internet gateway in a private subnet would expose the instance. Option C is wrong because VPC peering is for connecting VPCs, not internet access. Option D is wrong because a VPN does not provide internet access.
What should I do if I get this SCS-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 SCS-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
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 SCS-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 SCS-C02 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.