rpc.mountd - NFS mount daemon
The rpc.mountd program implements the NFS mount protocol. When receiving a MOUNT request
from an NFS client, it checks the request against the list of currently exported file sys-
tems. If the client is permitted to mount the file system, rpc.mountd obtains a file han-
dle for requested directory and returns it to the client.
Exporting NFS File Systems
Making file systems available to NFS clients is called exporting.
Usually, a file system and the hosts it should be made available to are listed in the
/etc/exports file, and invoking exportfs -a whenever the system is booted. The exportfs(8)
command makes export information available to both the kernel NFS server module and the
Alternatively, you can export individual directories temporarily using exportfs's
The rmtab File
For every mount request received from an NFS client, rpc.mountd adds an entry to the
/var/lib/nfs/rmtab file. When receiving an unmount request, that entry is removed. user
level part of the NFS service.
However, this file is mostly ornamental. One, the client can continue to use the file han-
dle even after calling rpc.mountd 's UMOUNT procedure. And two, if a client reboots with-
out notifying rpc.mountd , a stale entry will remain in rmtab.
-d kind or --debug kind
Turn on debugging for kind.
-F or --foreground
Run in foreground (do not daemonize)
-f or --exports-file
This option specifies the exports file, listing the clients that this server is
prepared to serve and parameters to apply to each such mount (see exports(5)). By
default, export information is read from /etc/exports.
-h or --help
Display usage message.
-o num or --descriptors num
Set the limit of the number of open file descriptors to num. The default is 256.
-N or --no-nfs-version
This option can be used to request that rpc.mountd do not offer certain versions of
NFS. The current version of rpc.mountd can support both NFS version 2 and the newer
version 3. If the NFS kernel module was compiled without support for NFSv3,
rpc.mountd must be invoked with the option --no-nfs-version 3 .
-n or --no-tcp
Don't advertise TCP for mount.
-P Ignored (compatibility with unfsd??).
-p or --port num
Force rpc.mountd to bind to the specified port num, instead of using the random
port number assigned by the portmapper.
-V or --nfs-version
This option can be used to request that rpc.mountd offer certain versions of NFS.
The current version of rpc.mountd can support both NFS version 2 and the newer ver-
-v or --version
Print the version of rpc.mountd and exit.
This rpc.mountd version is protected by the tcp_wrapper library. You have to give the
clients access to rpc.mountd if they should be allowed to use it. To allow connects from
clients of the .bar.com domain you could use the following line in /etc/hosts.allow:
You have to use the daemon name mountd for the daemon name (even if the binary has a dif-
For further information please have a look at the tcpd(8) and hosts_access(5) manual
rpc.nfsd(8), exportfs(8), exports(5), rpc.rquotad(8).
Olaf Kirch, H. J. Lu, G. Allan Morris III, and a host of others.
25 Aug 2000 rpc.mountd(8)