Access Control Lists (ACL)
The following sections on Access Control Lists (ACLs) applies only to FreeBSD 5.0. FreeBSD 4.x does not support ACLs).
Access Control Lists (ACLs) are a new addition to FreeBSD 5.0 that give you tighter control over who can and cannot access files and directories. Instead of just allowing or denying access based on owner, group, and everyone else, you can now grant access to individual users and individual groups. You can also set a maximum permission mask for the users and groups that are granted access through the ACL that will override the actual permissions given by the ACL.
For ACL to work, UFS extensions must be compiled into the kernel. The next section explains the options that must be added.