- A
A NAT Gateway in the public subnet.
Why wrong: NAT Gateway enables outbound internet from private subnets, not inbound.
- B
A network ACL rule on the private subnet allowing inbound traffic from the public subnet CIDR.
Network ACLs provide stateless filtering at the subnet level.
- C
An Internet Gateway attached to the VPC.
Why wrong: Internet Gateway is for internet traffic; internal traffic uses local routing.
- D
A VPC Endpoint for the database service.
Why wrong: VPC Endpoints are for accessing AWS services like S3, DynamoDB, not for EC2-to-database traffic.
- E
A security group rule on the database allowing inbound traffic from the EC2 instance's security group.
Security groups act as a virtual firewall for instances.
Question 499 of 1,546
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 has a VPC with a public subnet and a private subnet. The private subnet hosts a database. Which TWO components are required to allow an EC2 instance in the public subnet to connect to the database?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A network ACL rule on the private subnet allowing inbound traffic from the public subnet CIDR.
A security group rule on the database allowing inbound traffic from the EC2 instance's security group (Option E) is required because security groups act as a virtual firewall at the instance level, and by default they deny all inbound traffic. A network ACL rule on the private subnet allowing inbound traffic from the public subnet CIDR (Option B) is also required because network ACLs are stateless and control traffic at the subnet boundary; without an inbound allow rule, traffic from the public subnet would be dropped by the private subnet's ACL.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A NAT Gateway in the public subnet.
- ✓
A network ACL rule on the private subnet allowing inbound traffic from the public subnet CIDR.
Why this is correct
Network ACLs provide stateless filtering at the subnet level.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
An Internet Gateway attached to the VPC.
Why it's wrong here
Internet Gateway is for internet traffic; internal traffic uses local routing.
- ✗
A VPC Endpoint for the database service.
Why it's wrong here
VPC Endpoints are for accessing AWS services like S3, DynamoDB, not for EC2-to-database traffic.
- ✓
A security group rule on the database allowing inbound traffic from the EC2 instance's security group.
Why this is correct
Security groups act as a virtual firewall for instances.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the purpose of a NAT Gateway (outbound internet) with the need for subnet-to-subnet traffic, or they assume an Internet Gateway is required for any cross-subnet communication within a VPC.
Detailed technical explanation
How to think about this question
Security groups are stateful, meaning that if you allow inbound traffic from a source security group, the return traffic is automatically allowed regardless of outbound rules. Network ACLs are stateless, so you must explicitly allow both inbound and outbound traffic; in this scenario, the private subnet's NACL must have an inbound rule for the public subnet's CIDR and an outbound rule for ephemeral ports to allow response traffic. The VPC's internal router automatically routes traffic between subnets based on route tables, so no additional gateway is needed for subnet-to-subnet communication.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
Visual reference
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Networking and Content Delivery — study guide chapter
Learn the concepts, then practise the questions
- →
Networking and Content Delivery practice questions
Targeted practice on this topic area only
- →
All SOA-C02 questions
1,546 questions across all exam domains
- →
AWS Certified SysOps Administrator Associate SOA-C02 study guide
Full concept coverage aligned to exam objectives
- →
SOA-C02 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related SOA-C02 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Monitoring, Logging, and Remediation practice questions
Practise SOA-C02 questions linked to Monitoring, Logging, and Remediation.
Reliability and Business Continuity practice questions
Practise SOA-C02 questions linked to Reliability and Business Continuity.
Deployment, Provisioning, and Automation practice questions
Practise SOA-C02 questions linked to Deployment, Provisioning, and Automation.
Security and Compliance practice questions
Practise SOA-C02 questions linked to Security and Compliance.
Networking and Content Delivery practice questions
Practise SOA-C02 questions linked to Networking and Content Delivery.
Cost and Performance Optimization practice questions
Practise SOA-C02 questions linked to Cost and Performance Optimization.
SOA-C02 fundamentals practice questions
Practise SOA-C02 questions linked to SOA-C02 fundamentals.
SOA-C02 scenario practice questions
Practise SOA-C02 questions linked to SOA-C02 scenario.
SOA-C02 troubleshooting practice questions
Practise SOA-C02 questions linked to SOA-C02 troubleshooting.
Practice this exam
Start a free SOA-C02 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this SOA-C02 question test?
Networking and Content Delivery — This question tests Networking and Content Delivery — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: A network ACL rule on the private subnet allowing inbound traffic from the public subnet CIDR. — A security group rule on the database allowing inbound traffic from the EC2 instance's security group (Option E) is required because security groups act as a virtual firewall at the instance level, and by default they deny all inbound traffic. A network ACL rule on the private subnet allowing inbound traffic from the public subnet CIDR (Option B) is also required because network ACLs are stateless and control traffic at the subnet boundary; without an inbound allow rule, traffic from the public subnet would be dropped by the private subnet's ACL.
What should I do if I get this SOA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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 →
Keep practising
More SOA-C02 practice questions
- A company uses an Amazon DynamoDB table with on-demand capacity mode. The table handles a workload with a steady baselin…
- A company uses Amazon CloudWatch Logs to store application logs. The SysOps administrator needs to count the occurrences…
- A SysOps administrator needs to monitor the CPU utilization of an Amazon EC2 instance and send an alert when it exceeds…
- A SysOps administrator needs to monitor the CPU utilization of an Amazon EC2 instance fleet and send an alert when the a…
- A company's security policy requires that all Amazon S3 buckets must have server-side encryption enabled. The SysOps adm…
- A SysOps administrator uses AWS CloudFormation to deploy a stack that includes an Amazon EC2 instance. The administrator…
Last reviewed: Jul 4, 2026
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.