The correct answers are Network ACLs and Security Groups, as both are native AWS services designed specifically to control traffic within a VPC. Network ACLs act as a stateless firewall at the subnet level, meaning you must explicitly define rules for both inbound and outbound traffic, and each rule is evaluated independently without any connection tracking. Security Groups, in contrast, operate at the instance level as a stateful firewall, automatically allowing return traffic for permitted requests, which simplifies rule management. On the AWS Certified SysOps Administrator Associate SOA-C02 exam, this distinction is frequently tested to see if you understand when to use each service, with common traps including confusing Route Tables (which only direct traffic, not filter it) or assuming Internet Gateways provide security. A reliable memory tip is to remember that Security Groups are stateful like a smart doorman who remembers who left, while NACLs are stateless like a bouncer checking every single person both entering and leaving.
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.
Which TWO AWS services can be used to improve the security of a VPC? (Choose TWO.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Security Groups
Option A is correct because Network ACLs provide stateless filtering. Option D is correct because Security Groups provide stateful filtering. Option B is wrong because Route Tables control traffic routing, not security. Option C is wrong because Internet Gateway provides internet access. Option E is wrong because VPC Peering connects VPCs but does not add security.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Security Groups
Why this is correct
Correct because security groups act as virtual firewalls for instances.
Related concept
Standard ACLs match source addresses.
✗
Internet Gateway
Why it's wrong here
Incorrect because an IGW provides internet connectivity, not security.
✗
Route Tables
Why it's wrong here
Incorrect because route tables determine where traffic goes, not whether it's allowed.
✓
Network ACLs
Why this is correct
Correct because NACLs filter traffic at the subnet level.
Related concept
Standard ACLs match source addresses.
✗
VPC Peering
Why it's wrong here
Incorrect because peering connects VPCs but does not provide security filtering.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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 ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related SOA-C02 ACL questions on filtering logic and placement.
Networking and Content Delivery — This question tests Networking and Content Delivery — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: Security Groups — Option A is correct because Network ACLs provide stateless filtering. Option D is correct because Security Groups provide stateful filtering. Option B is wrong because Route Tables control traffic routing, not security. Option C is wrong because Internet Gateway provides internet access. Option E is wrong because VPC Peering connects VPCs but does not add security.
What should I do if I get this SOA-C02 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related SOA-C02 ACL questions on filtering logic and placement.
What is the key concept behind this question?
Standard ACLs match source addresses.
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 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
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.