You currently manage a set of web servers hosted on EC2 Servers with public IP addresses. These IP addresses are mapped to domain names. There was an urgent maintenance activity that had to be carried out on the servers and the servers had to be stopped and started again. Now the web application hosted on these EC2 Instances is not accessible via the domain names configured earlier. Which of the following could be a reason for this?

Answer options:

A.The Route53 hosted zone needs to be restarted.
B.The network interfaces need to be initialized again.
C.The public IP addresses need to be associated to the ENI again.
D.The public IP addresses have changed after the instance was stopped and started

Answer – D
By default, the public IP address of an EC2 Instance is released after the instance is stopped and started. Hence the earlier IP address which was mapped to the domain names would have become invalid now.
Options A, B and C are all invalid because these operations are not allowed in AWS.
For more information on public IP addressing, please visit the below URL:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-instance-addressing.html#concepts-public-addresses