The answer is that empty egress rules prevent web server access because the security group denies all outbound traffic by default. While the inbound rule correctly allows HTTP (80) from 0.0.0.0/0, the web server cannot send response packets back to users without a corresponding outbound rule. This is a classic AWS Certified Solutions Architect Professional SAP-C02 trap: candidates often focus only on inbound security group egress rules, forgetting that responses are treated as new outbound traffic. The exam tests your understanding that security groups are stateful for inbound traffic but require explicit outbound rules for initiated responses—a common point of confusion with network ACLs, which are stateless. Remember the memory tip: “Inbound opens the door, but outbound lets the reply out the window.”
SAP-C02 Design for New Solutions Practice Question
This SAP-C02 practice question tests your understanding of design for new solutions. 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
An administrator runs the above commands and observes the outputs. The instance is in a public subnet with an internet gateway. What is the most likely issue preventing users from accessing the web server?
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 security group does not allow outbound traffic, so responses cannot be sent.
Option B is correct because the security group allows inbound HTTP (80) from 0.0.0.0/0, but the egress rules are empty, which means all outbound traffic is denied. The web server cannot send responses back. Option A is wrong because HTTP port 80 is open. Option C is wrong because SSH is not required for web access. Option D is wrong because the security group allows HTTP.
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 security group allows SSH from a restricted IP, but not from the users.
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 for New Solutions — This question tests Design for New Solutions — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: The security group does not allow outbound traffic, so responses cannot be sent. — Option B is correct because the security group allows inbound HTTP (80) from 0.0.0.0/0, but the egress rules are empty, which means all outbound traffic is denied. The web server cannot send responses back. Option A is wrong because HTTP port 80 is open. Option C is wrong because SSH is not required for web access. Option D is wrong because the security group allows HTTP.
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.