nfs(6P)                         NFS 5.4R3.00                         nfs(6P)


NAME
       nfs, NFS - network file system

CONFIG
       options NFS

DESCRIPTION
       The Network File System, or NFS, allows a client workstation to
       perform transparent file access over the network.  Using it, a client
       workstation can operate on files that reside on a variety of servers,
       server architectures and across a variety of operating systems.
       Client file access calls are converted to NFS protocol requests, and
       are sent to the server system over the network.  The server receives
       the request, performs the actual file system operation, and sends a
       response back to the client.

       The Network File System operates in a stateless fashion using remote
       procedure (RPC) calls built on top of external data representation
       (XDR) protocol.  These protocols are documented in Managing ONC
       (Trademark)/NFS® and Its Facilities on the DG/UX (Trademark) System.
       The RPC protocol provides for version and authentication parameters
       to be exchanged for security over the network.

       A server can grant access to a specific filesystem to certain clients
       by adding an entry for that filesystem to the server's /etc/exports
       file and executing the exportfs -a command.

       A client gains access to that filesystem with the mount(2) system
       call, which requests a file handle for the filesystem itself.  Once
       the filesystem is mounted by the client, the server issues a file
       handle to the client for each file (or directory) the client
       accesses.  If the file is somehow removed on the server side, the
       file handle becomes stale (dissociated with a known file).

       A server may also be a client with respect to filesystems it has
       mounted over the network, but its clients cannot gain access to those
       filesystems.  Instead, the client must mount a filesystem directly
       from the server on which it resides.

       The user ID and group ID mappings must be the same between client and
       server.  However, the server maps uid 0 (the super-user) to uid 65534
       before performing access checks for a client.  This inhibits super-
       user privileges on remote filesystems.  A server can, however, allow
       root access for specific clients by making an entry in the
       /etc/exports file.

DIAGNOSTICS
       Generally physical disk I/O errors detected at the server are
       returned to the client for action.  If the server is down or
       inaccessible, the client will see the console message:
              NFS: file server not responding: still trying.
       For hard-mounted file systems, the client resends the request until
       it receives an acknowledgement from the server.  This means the
       server can crash or power down, and come back up, without any special



Licensed material--property of copyright holder(s)                         1

nfs(6P)                         NFS 5.4R3.00                         nfs(6P)


       action required by the client.

FILES
       /etc/exports

SEE ALSO
       exportfs(1M), mount(1M), mountd(1M), nfsd(1M), mount(2), exports(4),
       fstab(4).

















































Licensed material--property of copyright holder(s)                         2