Network ACL
A Network Access Control List (ACL) is a security layer that acts as a stateless firewall for controlling inbound and outbound traffic at the subnet level in cloud networks, such as AWS VPCs. It operates by evaluating rules based on IP addresses, ports, and protocols to allow or deny traffic, providing a basic level of network security. Unlike stateful firewalls, it does not track connection states, making it simpler but less granular for certain security needs.
Developers should learn and use Network ACLs when designing secure cloud infrastructures, particularly in AWS environments, to enforce network segmentation and protect resources from unauthorized access. They are essential for scenarios like isolating public and private subnets, blocking malicious IP ranges, or complying with security policies that require subnet-level traffic filtering. However, they should be combined with security groups for more comprehensive protection, as ACLs lack stateful inspection.