A small company started using EBS backed EC2 instances due to the cost improvements over running their own servers. The company’s policy is to stop the development servers over the weekend and restart them each week. The first time the servers were brought back. None of the developers were able to SSH into them. What did the server most likely overlook?

Answer options:

A.The associated Elastic IP address has changed and the SSH configurations were not updated.
B.The security group for a stopped instance needs to be reassigned after start.
C.The public IPv4 address has changed on server restart and the SSH configurations were not updated.
D.EBS backed EC2 instances cannot be stopped and were automatically terminated.

Correct Answer: C
Correct:
C. The instance retains its private IPv4 addresses and any IPv6 addresses when stopped and restarted. AWS releases the public IPv4 address and assigns a new one when it`s restarted.
Incorrect:
A. An EC2 instance retains its associated Elastic IP addresses.
B. Security groups do not need to be reassigned to instances that are restarted.
D. EBS backed instances are the only instance type that can be started and stopped.
Reference:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Stop_Start.html