The answer is to use Amazon CloudFront as a content delivery network (CDN). CloudFront caches your content at edge locations around the world, so when users request data, it is served from the nearest edge cache rather than directly from your EC2 instances. This drastically reduces the volume of data transferred from EC2 to the internet, which is the primary driver of those high egress costs. On the AWS Certified SysOps Administrator Associate SOA-C02 exam, this question tests your understanding of cost optimization for network traffic, often appearing as a scenario where you must distinguish between services that add cost (like NAT Gateways) and those that reduce it. A common trap is confusing VPC endpoints, which are for private AWS service access, with internet-facing data transfer reduction. Memory tip: think “Edge before Origin” — CloudFront’s edge caches serve first, sparing your EC2 origin from expensive internet egress.
SOA-C02 Cost and Performance Optimization Practice Question
This SOA-C02 practice question tests your understanding of cost and performance optimization. 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 SysOps administrator is reviewing the monthly AWS bill and notices a significant cost for data transfer from EC2 to the internet. The EC2 instances are in a VPC and serve content to users. Which action would MOST effectively reduce data transfer costs?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use Amazon CloudFront as a content delivery network (CDN).
Option C is correct because CloudFront caches content at edge locations, reducing data transfer from EC2 to the internet. Option A is wrong because using a NATGateway adds cost. Option B is wrong because VPC endpoints are for private connectivity to AWS services, not for reducing internet data transfer. Option D is wrong because moving to a different region does not reduce data transfer costs.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Use VPC endpoints to connect to S3 and DynamoDB.
Why it's wrong here
VPC endpoints reduce data transfer for AWS services, not internet traffic.
✓
Use Amazon CloudFront as a content delivery network (CDN).
Why this is correct
CloudFront reduces data transfer from EC2 by serving cached content from edge locations.
Related concept
Static NAT maps one inside address to one outside address.
✗
Move the EC2 instances to a different AWS Region with lower data transfer rates.
Why it's wrong here
Data transfer rates are similar across regions.
✗
Use a NAT Gateway to route traffic through a single IP.
Why it's wrong here
NATGateway does not reduce data transfer costs; it adds cost.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Trap categories for this question
Similar concept trap
Data transfer rates are similar across regions.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SOA-C02 NAT questions on configuration and troubleshooting.
Cost and Performance Optimization — This question tests Cost and Performance Optimization — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Use Amazon CloudFront as a content delivery network (CDN). — Option C is correct because CloudFront caches content at edge locations, reducing data transfer from EC2 to the internet. Option A is wrong because using a NAT Gateway adds cost. Option B is wrong because VPC endpoints are for private connectivity to AWS services, not for reducing internet data transfer. Option D is wrong because moving to a different region does not reduce data transfer costs.
What should I do if I get this SOA-C02 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SOA-C02 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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Question Discussion
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