What does a Network Access Control List (NACL) provide?

A Network Access Control List (NACL) is indeed a rule-based system designed specifically for controlling both inbound and outbound traffic at the subnet level within a Virtual Private Cloud (VPC) on AWS. It operates by implementing a set of rules that define which traffic is allowed or denied based on IP protocol, port number, and source/destination IP address. Each rule is evaluated in order, from lowest to highest priority, allowing for granular control over the traffic entering and leaving the network.

This type of access control is essential for network security, as it helps enforce policies and mitigate unauthorized access by effectively filtering traffic based on the defined rules. While other security mechanisms exist, such as security groups—which are stateful—NACLs are stateless, meaning that rules must be defined for both inbound and outbound traffic separately.

Other options refer to different types of security measures or functionalities that do not accurately describe the purpose of a NACL. For example, application-level security relates to protecting applications from threats, typically managed by different security solutions. A stateful firewall dynamically tracks active connections and therefore does not align with the stateless nature of NACLs. Lastly, virtual machine migration is unrelated to network access control and focuses instead on moving virtual machines between hosts or