Comprehensive and Detailed Explanation From FortiOS 7.6, FortiWeb 7.4 Exact Extract study guide:
As per theFortiOS 7.6 AWS Administration GuideandFortiWeb 7.4cloud deployment documentation, understanding the AWS infrastructure layer is critical for integrating Fortinet virtual appliances. The two features that define AWS Network Access Control Lists (NACLs) are:
* Stateless Nature (Option A):Unlike Security Groups, which are stateful (automatically allowing return traffic), NACLs arestateless. This means that if you allow inbound traffic on a specific port, you must also explicitly configure an outbound rule to allow the response traffic to leave the subnet. NACLs evaluate inbound and outbound traffic independently.
* Default Configuration (Option C):Every VPC comes with adefault NACL. By default, this NACL is configured toallow all inbound and outbound traffic. This is designed to ensure connectivity is not blocked until a custom security posture is defined. However, any custom NACL created manually starts by denying all traffic until rules are added.
Why other options are incorrect:
* Option B:NACLs are associated at thesubnet level, not the instance level. Security Groups are the components tied directly to an instance's Elastic Network Interface (ENI).
* Option D:NACLs and Security Groups providedefense-in-depthand are designed to be used simultaneously. Traffic must pass through the NACL (subnet level) and then the Security Group (instance level) to reach its destination.