Access Control List (ACL)


An Access Control List (ACL) is a list of rules that define which traffic is allowed or denied access to a network resource. ACLs are implemented on networking devices like routers, firewalls, and switches to control data flow and enforce security policies.

How ACLs Work

ACLs contain a set of rules, each specifying criteria for matching network packets. These criteria can include:

When a packet arrives, the networking device compares it against the ACL rules in sequential order. If a match is found, the corresponding action (permit or deny) is taken. If no match is found, a default action (usually to deny) is applied.

Benefits of ACLs

Common Use Cases