AWS Certified Advanced Networking – Specialty (ANS-C00) — Question 36

A legacy, on-premises web application cannot be load balanced effectively. There are both planned and unplanned events that cause usage spikes to millions of concurrent users. The existing infrastructure cannot handle the usage spikes. The CIO has mandated that the application be moved to the cloud to avoid further disruptions, with the additional requirement that source IP addresses be unaltered to support network traffic-monitoring needs. Which of the following designs will meet these requirements?

Answer options

• A. Use an Auto Scaling group of Amazon EC2 instances behind a Classic Load Balancer.
• B. Use an Auto Scaling group of EC2 instances in a target group behind an Application Load Balancer.
• C. Use an Auto Scaling group of EC2 instances in a target group behind a Classic Load Balancer.
• D. Use an Auto Scaling group of EC2 instances in a target group behind a Network Load Balancer.

Correct answer: D

Explanation

The correct answer is D because a Network Load Balancer operates at the transport layer and preserves the original source IP addresses, which is necessary for network traffic monitoring. Options A and C use Classic Load Balancers, which do not maintain the source IP. Option B utilizes an Application Load Balancer, which also alters the source IP, making it unsuitable for this requirement.