DOP-C02 Incident and Event Response Practice Question
A company experiences an unexpected spike in network traffic to a web application hosted on EC2 instances behind an Application Load Balancer. The DevOps team needs to investigate the source IP addresses generating the traffic. Which AWS service should they use to capture the traffic?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
VPC Flow Logs
VPC Flow Logs capture IP traffic information, including source and destination IPs, ports, and protocols, allowing investigation of source IPs. Option A (CloudWatch Logs) is wrong because it captures application logs, not network traffic. Option B (AWS Config) is wrong because it records resource configuration changes. Option C (CloudTrail) is wrong because it logs API calls, not network traffic.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon CloudWatch Logs
Why it's wrong here
Amazon CloudWatch Logs is a managed service for ingesting, storing, and monitoring log files emitted by applications, operating systems, and AWS services; it does not natively capture or record network flow data. To use it for a traffic spike, VPC Flow Logs would first need to publish records to a CloudWatch Logs group, but CloudWatch itself adds no packet-level visibility. Therefore it cannot be the source that reveals the IP addresses, ports, and byte counts driving the unexpected spike.
- ✗
AWS Config
Why it's wrong here
AWS Config is a configuration audit and compliance service that records configuration item history — such as security group rule additions, instance type changes, and resource deletions — and evaluates them against desired policies. While a change like opening a security group port might contribute to a traffic spike, AWS Config has no view of data-plane traffic or packet counts. It can answer what changed in your infrastructure, not what is currently flowing across the network.
- ✗
AWS CloudTrail
Why it's wrong here
AWS CloudTrail captures API activity in the management plane, logging every call made by an IAM user or service — like RunInstances, ModifySecurityGroupRules, or CreateFlowLogs — along with the actor, source IP, and timestamp. A spike in application-level network traffic to an existing workload typically does not generate API calls and thus will be invisible to CloudTrail. At best, CloudTrail might show correlated control-plane events, but it cannot provide the per-flow source/destination and byte metrics that a traffic investigation requires.
- ✓
VPC Flow Logs
Why this is correct
VPC Flow Logs capture IP traffic metadata for every network interface in a VPC, subnet, or at the interface level, recording source and destination IP addresses, ports, protocol, packet/byte counts, and whether the action was accepted or rejected by security groups and network ACLs. Enabling flow logs on the affected VPC or subnets would immediately provide the raw data needed to identify the top talkers, unusual port usage, or malicious sources behind the spike. This makes it the correct service for diagnosing an unexpected increase in network traffic.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DOP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DOP-C02 exam.