An Access Control List (ACL) governs who has access to resources in a computing environment. They are made up from individual Access Control Entries (ACE). Each ACE specifies a trustee to a particular resource, and what sort of access that trustee has to the resource. Access Control Lists can be used to allow access, deny access or audit access requests. They can be used across multiple resource types. For example, on file servers to control access to files, on directory servers like Active Directory Domain Controllers to control access to directory objects, and on network equipment they are used to control access to network services and ports.