Exam AWS Certified DevOps Engineer - Professional DOP-C02 topic 1 question 18 discussion

D "To support IPv6, configure your Application Load Balancers or Network Load Balancers with the “dualstack” IP address type. This means that clients can communicate with the load balancers using both IPv4 and IPv6 addresses. In a dual-stack IP address type, the DNS name of the load balancer provides both IPv4 and IPv6 addresses, and creates A and AAAA records respectively. " https://docs.aws.amazon.com/whitepapers/latest/ipv6-on-aws/scaling-the-dual-stack-network-design-in-aws.html

But why is port 443 necessary?

The correct answer is D. Add an IPv6 CIDR block to the VPC and subnets for the ALB. Create a listener on port 443. and specify the dualstack IP address type on the ALB. Create a target group, and add the EC2 instances as targets. Associate the target group with the ALB.

Why is the need for port 443 reference on D and D has no reference to private subnet. That makes me think the answer is A, but A has no reference to ALB.

D is correct: use dual stack + listener on 443 A: no mention of the ALB B: no mention of adding dualstack IP to ALB C: cannot replace the ALB

definitely D

keyword is "Dualstack"

D is correct , To enable ALB to deal with Ipv6 requests , vpc should enable for dual stack, by configuring a ipv6 cidr , and ALB subnet should also adhere to the same , by having ipv4 and 6 cidr B is incorrect , we can assisg any public ip to instance , since it is in private subnet .

D is the correct answer. C is wrong, we don't need Elastic IPs for a private app.

D i answer

I would say it is D. The backend instances serving the data can be IPv4. The ALB shoult serve IPv6 to the public (which is what is required by the question). So the only place in the VPC that needs IPv6 are the ALB subnets.

D is the correct answer in this case

To allow IPv6 clients to access the web service running on Amazon EC2 instances in a private subnet behind an Application Load Balancer (ALB) using an AWS CloudFormation template, the DevOps engineer should choose option D: Add an IPv6 CIDR block to the VPC and subnets for the ALB. Create a listener on port 443, and specify the dualstack IP address type on the ALB. Create a target group, add the EC2 instances as targets, and associate the target group with the ALB. The dualstack IP address type enables the ALB to support both IPv4 and IPv6 traffic. By adding an IPv6 CIDR block to the VPC and subnets for the ALB, the VPC automatically assigns an IPv6 address to the ALB.

D https://repost.aws/ja/knowledge-center/elb-configure-with-ipv6

answer is D

D right

I think D