ANS-C01 Question 120
Select 2Your organization is running a multi-tier web application in a VPC on AWS. Recently, users have reported intermittent connection issues. You need to identify the root cause by analyzing network traffic. Your architecture includes a fleet of EC2 instances in private subnets behind an Application Load Balancer (ALB). Which combination of actions will provide the necessary visibility into the network traffic to troubleshoot the issue? (Select TWO)
- A
Enable VPC Flow Logs for the VPC and configure them to send logs to Amazon CloudWatch Logs.
- B
Use Traffic Mirroring to replicate the network traffic from the EC2 instances to a monitoring instance.
- C
Enable Access Logs on the Application Load Balancer (ALB) and configure them to send logs to Amazon S3.
- D
Use AWS Network Firewall to capture all incoming and outgoing traffic for the VPC.
- E
Create a CloudWatch dashboard to monitor all metrics for the EC2 instances.
Show answer and explanation
Correct answers: A, B
Explanation
To troubleshoot intermittent connection issues, you need granular visibility into the network traffic. VPC Flow Logs provide detailed information about the IP traffic at the network interface level, and Traffic Mirroring enables you to analyze the actual packets being sent and received by EC2 instances. These tools together give you the network-level insights needed to identify and resolve the issue.
- A. Correct.
Enabling VPC Flow Logs provides visibility into the IP traffic at the network interface level, which is useful for detecting and analyzing potential connectivity issues.
- B. Correct.
Traffic Mirroring allows you to replicate the network traffic from EC2 instances to a monitoring instance for deep packet inspection and troubleshooting.
- C. Incorrect.
While enabling Access Logs on the ALB can provide useful information about requests sent to the load balancer, it does not offer visibility into the network traffic at the EC2 instance level.
- D. Incorrect.
AWS Network Firewall is a managed service for traffic inspection, but it is not intended for troubleshooting specific EC2 traffic patterns or connectivity issues.
- E. Incorrect.
Creating a CloudWatch dashboard can help monitor performance metrics but does not provide detailed network traffic visibility for troubleshooting.