You have set up an EC2 Instance that hosts a web application. You have set the following rules.
 Security Group Rules
Allow Inbound Traffic on port 80 from 0.0.0.0/0
NACL Rules
Allow Inbound Traffic on port 80 from 0.0.0.0/0
Users are complaining that they cannot access the web server. How can you ensure that the issue gets resolved?

Answer options:

A.Allow Outgoing Traffic on the Security groups for port 80.
B.Allow Outgoing Traffic on the NACL for port 80.
C.Allow Outgoing Traffic on the Security groups for ephemeral ports.
D.Allow Outgoing Traffic on the NACL for ephemeral ports.

Answer – D
This is also given in the AWS Documentation.
The client that initiates the request chooses the ephemeral port range. The range varies depending on the client`s operating system. Many Linux kernels (including the Amazon Linux kernel) use ports 32768-61000. Requests originating from Elastic Load Balancing use ports 1024-65535. Windows operating systems through Windows Server 2003 use ports 1025-5000. Windows Server 2008 and later versions use ports 49152-65535. A NAT gateway uses ports 1024-65535. For example, if a request comes into a web server in your VPC from a Windows XP client on the Internet, your network ACL must have an outbound rule to enable traffic destined for ports 1025-5000.
Options A and C are incorrect since Security groups are stateful. Hence you don’t need to open the outbound rules here.
Option B is incorrect since only the incoming traffic should accept port 80.
For more information on ephemeral ports, please refer to the below URL
https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_ACLs.html#VPC_ACLs_Ephemeral_Ports