AIX® ACL

The AIXC ACL is an access control list that is a proprietary of AIX servers.

It is not defined by the NFS version 4 protocol, and it is understood only by AIX servers and clients.

On an NFS version 4 server, AIXC ACL is supported when the underlying file system instance support AIXC ACL. All instances of JFS and JFS2 support the AIXC ACL.

An NFS version 4 client has a mount option that enables or disables support for AIX ACL. The default is to not support AIXC ACL. A user on an NFS version 4 client file system is able to read and write AIXC ACL when both the client and the server are running AIX, the underlying physical file system instance on the server supports AIXC ACL, and the AIX client mounts the file system instance with AIXC ACL enabled. AIXC ACL support in NFS version 4 is similar to the AIXC ACL support in AIX NFS version 2 and NFS version 3 implementations.

All instances of a JFS2 file system with extended attribute version 2 support both AIXC ACL and NFS4 ACL. A file in this type of file system may have mode bits only (no ACL), an NFS4 ACL, or an AIXC ACL. But, it cannot have NFS4 ACL and AIXC ACL at the same time.

The aclgettypes command can be used to determine the ACL types the can be read and written on a file system instance. This command may return different output when it runs against a physical file system on an NFS version 4 server locally than when it runs against the same file system on a NFS version 4 client. For example, a NFS version 4 file system instance on and NFS version 4 server may support NFS4 ACL and AIXC ACL, but the client is only configured to send and receive NFS4 ACL. In this case, when the aclgettypes command is executed from an NFS version 4 client file system, only NFS4 is returned. Also, if a user on the client requests an AIXC ACL, an error is returned.