AWS Certified Solutions Architect – Professional (SAP-C02) — Question 87
A company has VPC flow logs enabled for Its NAT gateway. The company is seeing Action = ACCEPT for inbound traffic that comes from public IP address 198.51.100.2 destined for a private Amazon EC2 instance.
A solutions architect must determine whether the traffic represents unsolicited inbound connections from the internet. The first two octets of the VPC CIDR block are 203.0.
Which set of steps should the solutions architect take to meet these requirements?
Answer options
- A. Open the AWS CloudTrail console. Select the log group that contains the NAT gateway's elastic network interface and the private instance's elastic network interlace. Run a query to filter with the destination address set as "like 203.0" and the source address set as "like 198.51.100.2". Run the stats command to filter the sum of bytes transferred by the source address and the destination address.
- B. Open the Amazon CloudWatch console. Select the log group that contains the NAT gateway's elastic network interface and the private instance's elastic network interface. Run a query to filter with the destination address set as "like 203.0" and the source address set as "like 198.51.100.2". Run the stats command to filter the sum of bytes transferred by the source address and the destination address.
- C. Open the AWS CloudTrail console. Select the log group that contains the NAT gateway's elastic network interface and the private instance’s elastic network interface. Run a query to filter with the destination address set as "like 198.51.100.2" and the source address set as "like 203.0". Run the stats command to filter the sum of bytes transferred by the source address and the destination address.
- D. Open the Amazon CloudWatch console. Select the log group that contains the NAT gateway's elastic network interface and the private instance's elastic network interface. Run a query to filter with the destination address set as "like 198.51.100.2" and the source address set as "like 203.0". Run the stats command to filter the sum of bytes transferred by the source address and the destination address.
Correct answer: B
Explanation
The correct answer is B because using Amazon CloudWatch allows monitoring of VPC flow logs effectively. The filter should check for the destination address that matches the VPC CIDR block, which is 203.0, while also tracking the source address of 198.51.100.2 to determine the traffic's legitimacy. Options A, C, and D are incorrect due to the use of AWS CloudTrail, which does not provide the necessary flow log information needed for this analysis.