The answer is the subnet’s auto-assign public IP setting being disabled, because without this setting enabled, EC2 instances launched in that subnet are not automatically assigned a public IPv4 address. Even with a correct route table pointing 0.0.0.0/0 to an internet gateway and the gateway attached, an instance needs a public IP to be reachable from and to send traffic to the internet; the internet gateway performs one-to-one NAT only for instances with a public IP. On the AWS Certified Solutions Architect Professional SAP-C02 exam, this scenario tests your understanding of the distinction between routing and IP address assignment—a common trap is assuming a default route alone guarantees internet access. Remember the memory tip: “Route gets you to the door, but a public IP is the key to open it.”
SAP-C02 Practice Question: Design Solutions for Organizational Complexity
This SAP-C02 practice question tests your understanding of design solutions for organizational complexity. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Network Topology
Refer to the exhibit. A solutions architect is troubleshooting why EC2 instances launched in subnet-11111111 cannot access the internet. The subnet is in a VPC with an internet gateway attached. The route table for the subnet has a default route (0.0.0.0/0) pointing to the internet gateway. What is the MOST likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The subnet's auto-assign public IP setting is disabled
Option C is correct because MapPublicIpOnLaunch is false, so instances launched in the subnet are not assigned public IP addresses automatically. Without a public IP, they cannot communicate with the internet via the internet gateway. Option A is wrong because the route to the internet gateway exists. Option B is wrong because the internet gateway is attached. Option D is wrong because NAT gateway is not required if the subnet had public IPs.
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.
✓
The subnet's auto-assign public IP setting is disabled
Why this is correct
MapPublicIpOnLaunch is false, so instances lack public IPs.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
The subnet needs a NAT gateway for internet access
Why it's wrong here
A NATgateway is needed for private subnets, but this subnet can be public if it assigns public IPs.
✗
The subnet's route table does not have a route to the internet gateway
Why it's wrong here
The exhibit states the route exists.
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 SAP-C02 subnetting questions on CIDR, address ranges, and subnet selection.
Design Solutions for Organizational Complexity — This question tests Design Solutions for Organizational Complexity — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: The subnet's auto-assign public IP setting is disabled — Option C is correct because MapPublicIpOnLaunch is false, so instances launched in the subnet are not assigned public IP addresses automatically. Without a public IP, they cannot communicate with the internet via the internet gateway. Option A is wrong because the route to the internet gateway exists. Option B is wrong because the internet gateway is attached. Option D is wrong because NAT gateway is not required if the subnet had public IPs.
What should I do if I get this SAP-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 SAP-C02 subnetting questions on CIDR, address ranges, and subnet selection.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 SAP-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 SAP-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.