You have configured a web server listening on port 80 on an EC2 Instance. You are trying to reach the home page of the web server but are not able to do so. You’ve checked that the Internet gateway is attached to the VPC , and the route tables have been modified accordingly. You have also attached an Elastic IP address to the EC2 Instance. Which of the following could be the cause for the underlying issue.

Answer options:

A.Check the Outbound Security Group rules, this could be denying the traffic on port 80.
B.Check the Inbound Rules for the NACL , this could be denying the traffic
C.You need to have a public IP defined for the EC2 Instance, since the Elastic IP will not work.
D.Change the Internet gateway as there could be an issue with the Internet gateway.

Answer – B
If you have a DENY rule as shown below for the port traffic which is lower in precedence for the NACL, this could also be a reason as to why the traffic is being blocked.
For more information on NACL, please visit the below link:
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_ACLs.html