Network ACL (NACL) is an AWS network firewall that controls inbound and outbound traffic at the subnet level in a Virtual Private Cloud (VPC). It adds an extra layer of security for your network.
With a Network ACL, you can allow or deny traffic based on IP addresses, ports, and protocols. Unlike Security Groups, NACLs are stateless, so you must create separate rules for inbound and outbound traffic.
In simple words, a Network ACL (NACL) protects an entire subnet by controlling which network traffic is allowed or denied.