AWS Certified Solutions Architect – Professional SAP-C01 – Question203

An EC2 instance that performs source/destination checks by default is launched in a private VPC subnet. All security, NACL, and routing definitions are configured as expected. A custom NAT instance is launched.
Which of the following must be done for the custom NAT instance to work?

A.
The source/destination checks should be disabled on the NAT instance.
B. The NAT instance should be launched in public subnet.
C. The NAT instance should be configured with a public IP address.
D. The NAT instance should be configured with an elastic IP address.

Correct Answer: A

Explanation:

Explanation: 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. However, a NAT instance must be able to send and receive traffic when the source or destination is not itself. Therefore, you must disable source/destination checks on the NAT instance.
Reference:
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_NAT_Insta…