Mac OS X Lion Server For Dummies®

Permission Schemes: POSIX Permissions and ACLs

Lion Server offers two different types of permissions for files and folders: Portable Operating System Interface for Unix (POSIX) permissions from the Unix world and access control lists (ACLs) from the Windows world. POSIX permissions are easier to use, but ACLs give you a finer degree of control over access to files and folders. Keep in mind, however, that ACLs are more complicated to manage.

POSIX permissions allow only one owner and one group setting for a shared folder. POSIX permissions don't provide different permissions to different individual users. ACLs allow multiple individuals and multiple groups to have different permissions for a shared folder. ACLs can be useful if you have several departments in the organization that need different levels of access for the same shared folder.

Table 8-1 shows the permission types that each file-sharing protocol can use. Chapter 9 describes the file-sharing protocols in further detail, but here's the gist: Apple Filing Protocol (AFP) is the best to use for Mac clients, and Server Message Block (SMB) is the best to use for Windows clients. Lion offers the WebDAV protocol for file sharing for iOS devices (iPad, iPhone, and iPod touch).

Table 8-1 Permission Types Available to File-Sharing Protocols

Two other file sharing protocols, NFS (Network File Sharing) and FTP (File Transfer Protocol), ...