What is access lists?

Access Control Lists (ACLs) are fundamental security features used in networking and operating systems to filter traffic or control access to resources. They are essentially ordered lists of rules that specify conditions for allowing or denying network traffic based on source/destination IP addresses, ports, protocols, and other criteria. ACLs are commonly used on routers, firewalls, and switches to implement security policies, such as blocking unauthorized access to internal networks or restricting specific types of traffic. They are also used on operating systems to manage file system permissions and control which users or processes can access certain files or directories.