Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A company has a VPC with public and private subnets. The private subnets need outbound internet access to download software updates while preventing any inbound internet traffic. The SysOps administrator must minimize costs. 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
Create a NAT Gateway in a public subnet and update the private subnet route table to use it
NAT Gateway is a managed service that is easier to set up, but it incurs higher hourly and data processing costs compared to a NAT instance.
B
Best answer
Launch a NAT instance in a public subnet with an Elastic IP and disable source/destination check, then update private subnet route tables
A NAT instance costs less per hour than a NAT Gateway, making it the more cost-effective option when minimizing costs is the primary goal.
C
Distractor review
Attach an Internet Gateway to the VPC and add a default route to the Internet Gateway in the private subnets
An Internet Gateway alone does not allow private subnets to initiate outbound traffic; a NAT device is required.
D
Distractor review
Use AWS Transit Gateway with a VPN connection to an on-premises data center for internet access
Transit Gateway with VPN is more complex and expensive, and it would route traffic on-premises even for internet access, which is inefficient.
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: Launch a NAT instance in a public subnet with an Elastic IP and disable source/destination check, then update private subnet route tables — To provide outbound internet access for private subnets, a NAT device is required. A NAT instance (a single EC2 instance with an Elastic IP and source/destination check disabled) is less expensive per hour than a NAT Gateway, especially for low throughput. While NAT Gateway is managed and more reliable, the question specifically emphasizes minimizing costs, making the NAT instance the more cost-effective choice. However, note that the NAT instance introduces operational overhead for patching and high availability. In exam contexts, 'minimize costs' often leads to NAT instance if the workload allows. An Internet Gateway attached to the VPC with routes in private subnets would not work without a NAT device. Transit Gateway with VPN is unnecessary for the stated requirement and costly.
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.
Discussion
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