Amazon VPC Network Access Control List Icon

Amazon VPC Network Access Control Lists (ACLs) act like firewalls for your virtual private cloud (VPC), controlling inbound and outbound traffic to subnets. They filter traffic based on pre-defined rules you specify, allowing or denying traffic based on IP address, port number, and protocol. ACLs are applied at the subnet level and are an additional security layer working in conjunction with other security features such as security groups to protect your resources within the VPC.