Choosing between PC-style or UNIX-style permissions

About this section

When you configure the CIFS protocol, you must choose whether the filer uses PC-style or UNIX-style permissions.

Note: If you are setting up a filer in a Windows NT-only environment, you can skip this section.

This section provides a brief overview of PC-style and UNIX-style permissions and provides guidelines for choosing which style to use. PC-style permissions are similar to FAT (File Allocation Table); they maintain security with share level ACLs (Access Control Lists). In addition, PC-style permissions also allow you to further restrict file security using file permissions. UNIX-style permissions do not use share level ACLs. Therefore, using PC-style permissions only affects PC access to files with UNIX security.

How PC-style permissions work

PC-style permissions are determined by the rights assigned in a share's ACL and are limited by the UNIX permissions assigned to a file. To write to a file when PC-style permissions are in effect, a user must meet the following criteria:

• The user must have write permission for the file in the ACL.
• The user must have write permission for the file according to the UNIX-style permissions associated with the file.

  If the user is the owner of the file, the filer uses the UNIX-style permissions set for the owner of the file. If the user is not the owner of the file, the filer uses the UNIX-style permissions set for the UNIX group associated with the file. Note that the UNIX "other" permissions are not used.

When to choose PC-style permissions

Choose PC-style permissions if you need file access to be controlled by ACLs.

How UNIX-style permissions work

UNIX-style permissions are determined by the rights associated with the UNIX UID and GID and are limited by the ACL permissions assigned to a file. To write to a file when UNIX-style permissions are in effect, a user must meet the following criteria:

• If the user is the owner of the file, the write permission for the user's UID must be set.
• If the user is not the owner of the file, he or she must be a member of the group (GID) associated with the file and the write permission for the group's GID must be set.
• The user must have write permission for the file in the ACL.

When to choose UNIX-style permissions

Choose UNIX-style permissions if you want to implement simple security and need access to be controlled using exact UNIX rules.

Note: If you choose UNIX-style permissions, set the share ACL permission to rwx for everyone. With this setting, the UNIX rights work just as they do on a UNIX system.

Copyright © 1999, Network Appliance, Inc. All rights reserved.

Part No. 210-02343
File: cifs_in2.htm
Last updated: 02/25/99 17:35:17