Question

A network engineer is troubleshooting an application that experiences intermittent connection failures between an EC2 instance in a private subnet and an RDS database in another subnet within the same VPC. A previous Reachability Analyzer path analysis between the two ENIs returned a status of 'Reachable', yet users still report periodic timeouts during peak traffic hours. Which action will best help the engineer identify the root cause of the intermittent failures?

Accepted Answer

Enable VPC Flow Logs on the relevant ENIs and analyze REJECT records and packet counts during the peak time windows to detect capacity or connection-limit issues.

Answer

Re-run Reachability Analyzer repeatedly during peak hours, since it evaluates live packet delivery and will capture the transient drops.

Answer

Increase the Reachability Analyzer maximum aggregation interval so it samples traffic more frequently and reveals dropped packets.

Answer

Add a security group rule allowing all traffic between the instance and database, because Reachability Analyzer cannot evaluate stateful rules.