Protecting Against Incoming Traffic Requests in a VPC Subnet

Answer - D.

The AWS Documentation mentions the following:

A network access control list (ACL) is an optional layer of security for your VPC that acts as a firewall for controlling traffic in and out of one or more subnets.

You might set up network ACLs with rules similar to your security groups in order to add an additional layer of security to your VPC.

For more information on Network ACL, please visit the URL:

The security feature associated with a subnet in a VPC (Virtual Private Cloud) that protects against incoming traffic requests is the "Network Access Control Lists" (ACLs), which is the answer D.

Network ACLs are stateless, which means that they apply rules to inbound and outbound traffic separately, unlike Security Groups (answer C) that are stateful and allow traffic to return automatically. Network ACLs are associated with subnets and act as a firewall to control traffic flow at the subnet level.

By default, a new subnet in a VPC comes with a Network ACL that allows all traffic in and out of the subnet. However, you can create custom Network ACLs and associate them with your subnets to add an additional layer of security by allowing or denying traffic based on the rules that you set.

AWS Inspector (answer A) is a security service that helps improve the security and compliance of your applications that are deployed on Amazon EC2 instances. It provides a detailed assessment of your application's security posture by analyzing the behavior of your AWS resources and identifying potential security issues.

Subnet Groups (answer B) is not a security feature, but a logical grouping of subnets within a VPC that share the same route table. They are useful for simplifying the management of multiple subnets that need to use the same set of route rules.

In summary, the correct answer to the question is D. Network ACLs.