Exam AWS Certified Advanced Networking - Specialty ANS-C01 topic 1 question 194 discussion

Exam question from Amazon's AWS Certified Advanced Networking - Specialty ANS-C01

Question #: 194
Topic #: 1

[All AWS Certified Advanced Networking - Specialty ANS-C01 Questions]

A company is using an Amazon CloudFront distribution that is configured with an Application Load Balancer (ALB) as an origin. A network engineer needs to implement a solution that requires all inbound traffic to the ALB to come from CloudFront. The network engineer must implement the solution at the network layer rather than in the application.

Which solution will meet these requirements in the MOST operationally efficient way?

A. Add an inbound rule to the ALB's security group to allow the AWS managed prefix list for CloudFront.
B. Add an inbound rule to the network ACLs that are associated with the ALB's subnets. Use the AWS managed prefix list for CloudFront as the source in the rule.
C. Configure CloudFront to add a custom HTTP header to the requests that CloudFront sends to the ALB.
D. Associate an AWS WAF web ACL with the ALB. Configure the AWS WAF rules to allow traffic from the CloudFront IP set. Automatically update the CloudFront IP set by using an AWS Lambda function.

Show Suggested Answer

Suggested Answer: A 🗳️

by seochan at May 30, 2024, 1:42 a.m.

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Comments

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veyisceylan

Highly Voted 1 year ago

It is asking a solution at network layer rather than application layer. Therefore it is A in my opinion. A managed prefix list is a set of one or more CIDR blocks. You can use prefix lists to make it easier to configure and maintain your security groups and route tables.

upvoted 6 times

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AzureDP900

Most Recent 6 months, 1 week ago

Selected Answer: A

A is right Adding an inbound rule to the ALB's security group to allow the AWS managed prefix list for CloudFront ensures that only traffic coming from CloudFront is allowed to reach the ALB. This meets the requirement of having all inbound traffic to the ALB come from CloudFront.

upvoted 2 times

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woorkim

6 months, 3 weeks ago

Selected Answer: A

AWS Managed Prefix List for CloudFront: AWS provides a managed prefix list that includes the IP ranges for CloudFront edge locations. By using this list in the ALB's security group, the network engineer can restrict access to only traffic originating from CloudFront without manually managing IP ranges. Operational Efficiency: This approach is operationally efficient because: The managed prefix list is automatically updated by AWS whenever CloudFront's IP ranges change. Security groups are simple to configure and maintain compared to other options like network ACLs or AWS WAF.

upvoted 1 times

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Spaurito

8 months ago

C - This defines the solution https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/restrict-access-to-load-balancer.html

upvoted 1 times

Spaurito

7 months, 4 weeks ago

Have to change my answer to "A". A defined for the network layer requirement.

upvoted 1 times

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Akshay0403

11 months, 2 weeks ago

Selected Answer: A

Option A is the most operationally efficient solution as it leverages AWS managed prefix lists, ensuring up-to-date and secure traffic management to the ALB from CloudFront. Security groups provide a straightforward way to enforce network layer restrictions without additional administrative overhead or application changes. This aligns well with the requirement to implement a solution strictly at the network layer.

upvoted 3 times

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