Configuring VPC Flow Logs and Analyzing Log Data | AWS Certified DevOps Engineer - Professional Exam

VPC Flow Logs Information

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Question

To meet security compliance of the company, your manager asks you to configure VPC Flow Logs in all AWS accounts.

You create the flow logs in VPCs and use an S3 bucket to store the logs.

You also set up a Sumo Logic dashboard to help analyze the log data.

Which of the following information can you get from the VPC Flow Logs? (Select TWO.)

Answers

Explanations

Click on the arrows to vote for the correct answer

A. B. C. D. E.

Correct Answer - B, E.

VPC Flow Logs capture information about the IP traffic going to and from network interfaces in the VPC.

About the available fields in the Flow Logs records, please check https://docs.aws.amazon.com/vpc/latest/userguide/flow-logs.html.

Option A is incorrect: VPC Flow Logs can capture information such as source/destination IP addresses and ports.

The logs cannot capture the information of messages in an SQS queue.

Option B is CORRECT: Because by analyzing the IP traffic from the Flow Logs, users can get the load information and understand when an application has the most number of requests.

Option C is incorrect: VPC Flow Logs cannot reflect the time when CloudWatch customized alarms are raised in EC2 instances.

Option D is incorrect: VPC Flow Logs collect IP traffic in network interfaces of AWS services.

However the AWS S3 information is not collected by VPC Flow Logs.

Option E is CORRECT: Because VPC Flow Logs can collect the source addresses of incoming traffic.

Users can get the geographic information from the requests.

VPC Flow Logs is a feature that enables you to capture information about the traffic that moves in and out of a VPC (Virtual Private Cloud). It helps in gaining insight into network traffic patterns, detecting anomalous traffic behavior, and troubleshooting connectivity issues.

Given the scenario, VPC Flow Logs have been created in all VPCs and are stored in an S3 bucket. A Sumo Logic dashboard has also been set up to analyze the log data. Now, let's look at the information that can be obtained from the VPC Flow Logs:

A. The time when the messages in an SQS queue reach the limit. This information cannot be obtained from VPC Flow Logs. SQS (Simple Queue Service) is a messaging service, and it is not related to VPC network traffic.

B. The time of the day when your EC2 hosted web application experiences the heaviest load. This information cannot be directly obtained from VPC Flow Logs. However, you can indirectly infer this by monitoring the network traffic patterns during different times of the day. For example, if you notice a significant increase in traffic during a particular time, it could be an indication of high load on the EC2 instances.

C. The time when EC2 instances raise customized CloudWatch alarms. This information cannot be obtained from VPC Flow Logs. CloudWatch Alarms are generated based on metrics such as CPU utilization, network traffic, etc. that are monitored and collected by CloudWatch.

D. The number of objects that are written to S3 buckets owned by your AWS accounts. This information cannot be obtained directly from VPC Flow Logs. However, you can use AWS CloudTrail to monitor S3 bucket activity and track object-level operations such as creation, deletion, etc.

E. The geographic region that has the most users for your application. This information cannot be obtained directly from VPC Flow Logs. However, you can use the IP address information in the logs to determine the geographic location of the traffic sources.

In conclusion, the two pieces of information that can be obtained from VPC Flow Logs are:

  • The network traffic patterns and anomalies
  • The source and destination IP addresses of the traffic.