Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company has an Application Load Balancer (ALB) that routes traffic to Amazon EC2 instances in private subnets of a VPC. The SysOps administrator needs to ensure that the EC2 instances can download software updates from the internet, but they must not be directly accessible from the internet. The solution should minimize operational overhead. Which solution should the administrator implement?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Place the EC2 instances in a public subnet and configure security group inbound rules to block all traffic.
Instances in a public subnet have direct internet access but are still reachable from the internet if security groups are misconfigured; this does not guarantee the required security posture and does not fully prevent inbound traffic.
B
Best answer
Attach a NAT Gateway to a public subnet and configure the private subnet route table to send 0.0.0.0/0 traffic to the NAT Gateway.
A NAT Gateway enables outbound internet connectivity for instances in private subnets while blocking unsolicited inbound connections. It is fully managed, reducing operational overhead.
C
Distractor review
Launch a NAT instance in a public subnet with an Elastic IP address and configure route tables accordingly.
A NAT instance can provide similar functionality but requires manual configuration, patching, and scaling, increasing operational overhead. The question prioritizes minimizing overhead.
D
Distractor review
Attach an Internet Gateway to the VPC and add a route to the private subnet route table pointing 0.0.0.0/0 to the Internet Gateway.
Directly routing private subnet traffic to an Internet Gateway would give instances a public IP and expose them to inbound internet traffic, violating the security requirement.
Common exam trap
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.
Technical deep dive
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.
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.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A company uses Amazon CloudFront to deliver content to a global audience. The origin is an Application Load Balancer in us-east-1. The SysOps administrator wants to reduce costs by minimizing the number of requests that reach the origin server. Which action should the administrator take?
Question 2
A company runs a batch processing application on Amazon EC2 that runs for 2 hours every night. The workload can tolerate interruptions. Which EC2 purchasing option provides the lowest cost for this use case?
Question 3
A SysOps administrator needs to monitor the CPU utilization of an Amazon RDS DB instance and receive an alarm when CPU utilization exceeds 80% for 5 consecutive minutes. Which AWS service should be used to create this alarm?
Question 4
A company runs a critical web application on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The application uses session stickiness (sticky sessions) to maintain user sessions. The SysOps administrator notices that when instances are replaced during a scale-in or failure event, users lose their session data. The administrator needs to preserve session data across instance failures without losing stickiness benefits. What should the administrator do?
Question 5
A company runs a production web application on a single Amazon EC2 instance. The application experiences a predictable and steady workload 24/7. The SysOps administrator wants to minimize compute costs for this instance while ensuring it remains available during the expected workload. Which EC2 purchasing option should the administrator use?
Question 6
A company has a VPC with public and private subnets. The private subnets host application servers that need to make outbound HTTPS connections to the internet. The SysOps administrator must implement a solution that provides outbound internet connectivity while preventing inbound connections from the internet. Additionally, the solution must allow the company to control which domains the application servers can access. Which solution should the administrator implement?
FAQ
Questions learners often ask
What does this SOA-C02 question test?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: Attach a NAT Gateway to a public subnet and configure the private subnet route table to send 0.0.0.0/0 traffic to the NAT Gateway. — A NAT Gateway in a public subnet with updated route tables allows private instances to initiate outbound traffic to the internet while preventing unsolicited inbound connections. It is a managed service that requires minimal operational overhead compared to a self-managed NAT instance. A NAT instance (Option C) requires manual patching and scaling. An Internet Gateway (Option D) directly attached to private subnets would expose instances to inbound traffic if routes are misconfigured. Placing instances in a public subnet (Option A) would make them reachable from the internet, violating security requirements.
What should I do if I get this SOA-C02 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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