Mac OS X Lion Server For Dummies®

Propagating POSIX Permissions

When you configure file sharing, you generally set permissions for one or more shared folders (share points). Usually, users can create new files or folders and can copy files into a folder. Rather than having to set Owner and Group permissions for every new file and folder, these child folders and files are automatically assigned permissions based on rules.

All the file-sharing protocols can use the standard POSIX permissions behavior. The AFP and SMB protocols have another option for propagating POSIX permissions, dubbed Inherit Permissions from Parent or just Inherit Permissions. With this method, new files and folders inherit certain permissions from the parent folder (the folder in which the files and folders are created).

Standard POSIX permissions behavior

In the standard behavior, permissions are assigned for new files and folders on a share point, regardless of what the permissions are on the parent folder. New files or folders get these permissions:

• Owner: The user who created the new folder or file becomes the owner and is assigned read/write permissions.
• Group: The new file or folder inherits the group assigned to the parent folder; however, the group is assigned read-only permissions.
• Everyone/Other: Is assigned read-only permissions.

Files and folders copied to the share point or duplicated don't inherit any permissions from the parent folder:

• Owner: The user who created the folder or file remains the owner and is assigned read/write ...