You have 3 EC2 Instances that have public IP’s addresses that are mapped to DNS names in Route53. A peer administrator has advised that this may not be the ideal setup and that the DNS names could point to invalid IP addresses in the future. Which of the following can help ensure that this issue does not happen. Choose 2 answers from the options given below. Each option forms part of the solution.

Answer options:

A.Map the DNS names to the private IP addresses
B.Create Elastic IP’s and assign them to the EC2 Instances.
C.Map the DNS names to the Elastic IP’s
D.Ensure the Instances receive private IP addresses.

Answer – B and C
When the instance is stopped and started , the public IP assigned to the instance will change and hence this can result in broken DNS links. The ideal scenario is to have Elastic IP addresses and map them to the DNS host names
For more information on Elastic IP, please refer to the below URL:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/elastic-ip-addresses-eip.html