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. The servers had to be stopped and restarted. 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 Route 53 hosted zone needs to be restarted.
B.The network interfaces need to initialized again.
C.The public IP addresses need to be associated with the ENI again.
D.The public IP addresses have changed after the instance was stopped and started again.

Correct 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.
For more information on public IP address, please visit the URL below:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-instance-addressing.html#concepts-public-addresses
Note:
This only applies to IPv4 public addresses. IPv6 public address isn`t disassociated after an instance is stopped.