Exam AWS Certified SAP on AWS - Specialty PAS-C01 topic 1 question 59 discussion

C: When you use an overlay IP address for a cluster, AWS doesn't recognize that IP address as belonging to the EC2 instances in your cluster. By default, AWS only allows an instance to send and receive traffic with the IP address assigned to its network interface. For routing to work properly with an overlay IP address, you need to disable the source/destination check on the EC2 instances in the cluster.

for certain cases like the one described here, where the EC2 instances are being used for routing purposes (such as in a NAT scenario or with IBM Db2 high availability disaster recovery), this check needs to be disabled. This allows the EC2 instances to handle traffic that isn’t specifically destined for the instance itself, which seems to be the requirement in this scenario. Therefore, turning off the source/destination check on the database EC2 instances should allow the traffic to be routed correctly.

Option B is correct because creating route table entries to allow traffic from the database EC2 instances to the NAT gateway will resolve the issue of traffic not routing to the database EC2 instances. The NAT gateway is used to enable instances in a private subnet to connect to the internet or other AWS services but prevent the internet from initiating connections with the instances. Option C is incorrect because turning off the source/destination check for the database EC2 instances will not resolve the issue of traffic not routing to the database EC2 instances. The source/destination check is enabled by default on all Amazon EC2 instances. This feature must be disabled for instances that are used as NAT instances, and the DB instance is not being used as a NAT instance.

C is correct

Answer is C Disable the source/destination check Each EC2 instance performs source/destination checks by default. This means that the instance must be the source or destination of any traffic it sends or receives. For cluster instances, source/destination check must be disabled on both EC2 instances which are supposed to receive traffic from the Overlay IP address. You can use the AWS CLI or AWS Management Console to disable source/destination check. For details, see the ec2 modify-instance-attribute documentation. https://docs.aws.amazon.com/sap/latest/sap-hana/sap-hana-on-aws-cluster-configuration-prerequisites.html

C is correct

I think C

B: makes sense

I think C https://docs.aws.amazon.com/sap/latest/sap-hana/sap-hana-on-aws-cluster-configuration-prerequisites.html