AWS Certified Advanced Networking – Specialty (ANS-C01) — Question 153

A company uses multiple AWS accounts and VPCs in a single AWS Region. The company must log all network traffic for Amazon EC2 instances and Amazon RDS databases. The company will use the log information to monitor and identify traffic flows in the event of a security incident. The information must be retained for 12 months but will be accessed infrequently after the first 90 days. The company must be able to view metadata that includes the vpc-id, subnet-id: and tcp-flags fields.

Which solution will meet these requirements at the LOWEST cost?

Answer options

• A. Configure VPC flow logs with the default fields Store the logs in Amazon CloudWatch Logs.
• B. Configure Traffic Mirroring on all AWS resources to point to a Network Load Balancer that will send the mirrored traffic to monitoring instances.
• C. Configure VPC flow logs with additional custom format fields Store the logs in Amazon S3.
• D. Configure VPC flow logs with additional custom format fields Store the logs in Amazon CloudWatch Logs.

Correct answer: C

Explanation

The correct answer is C, as storing VPC flow logs in Amazon S3 is more economical for long-term storage and meets the 12-month retention requirement with infrequent access. Options A and D use CloudWatch Logs, which can be more expensive for this use case, especially considering the retention period, while B involves a more complex setup that would incur higher costs and does not directly address the logging requirement.