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Not to be confused with NTFS.


Network File System (NFS) is a file system protocol that allows client machines to access network attached filesystems.



NFS server support is not required for NFS clients, and NFS client support is not required for NFS servers. Inotify support is only required for NFSv4. NFSv3 is only required for compatibility with legacy clients e.g. the BusyBox mount command does not support NFSv4.

KERNEL Enabling NFS support
File systems --->
  [*] Inotify support for userspace
  [*] Network File Systems --->
        <*>   NFS client support
        <*>     NFS client support for NFS version 3
        <*>     NFS client support for NFS version 4
        [*]   NFS client support for NFSv4.1
        <*>   NFS server support
        [*]     NFS server support for NFS version 3
        [*]     NFS server support for NFS version 4
        [*]       NFSv4.1 server support for Parallel NFS (pNFS)

USE flags

USE flags for net-fs/nfs-utils NFS client and server daemons

caps Use Linux capabilities library to control privilege
ipv6 Add support for IP version 6
junction Enable NFS junction support in nfsref
kerberos Add kerberos support
ldap Add ldap support
libmount Link mount.nfs with libmount
nfsdcld Enable nfsdcld NFSv4 clientid tracking daemon
nfsidmap Enable support for newer nfsidmap helper
nfsv4 Enable support for NFSv4
nfsv41 Enable support for NFSv4.1
selinux !!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur
tcpd Add support for TCP wrappers
uuid Support UUID lookups in rpc.mountd


Install net-fs/nfs-utils:

root #emerge --ask net-fs/nfs-utils



The following table describes the filesystems that will be exported by the server:

Device Mount directory Description
/dev/sdb1 /home Filesystem containing user home directories.
/dev/sdc1 /data Filesystem containing user data.

Virtual root

The filesystems to be exported can be made available under a single directory. This directory is known as the virtual root directory:

root #mkdir /export
The /export directory is used throughout this article as the virtual root directory, although any directory can be used e.g. /nfs or /srv/nfs

Create directories in the virtual root directory for the filesystems (e.g. /home and /data) that are to be exported:

root #mkdir /export/home
root #mkdir /export/data

The filesystems to be exported need to be made available under their respective directories in the virtual root directory. This is accomplished with the --bind option of the mount command:

root #mount --bind /home /export/home
root #mount --bind /data /export/data

To make the above mounts persistent, add the following to /etc/fstab:

FILE /etc/fstab
/home    /export/home    none    bind    0    0
/data    /export/data    none    bind    0    0


The filesystems to be made accessible for clients are specified in /etc/exports. This file consists of the directories to be exported, the clients allowed to access those directories, and a list options for each client. Refer to man exports for more information about the NFS export configuration options:

FILE /etc/exports

The above configuration grants access to the exported directories by IP network, in this case Client access can also be specified as a single host (IP address or fully qualified domain name), NIS netgroup, or with a single * character which grants all clients access.

The following table briefly describes the client options used in the configuration above:

Option Description
insecure The server will require that client requests originate on unprivileged ports (those above 1024). This option is required when mounting exported directories from OS X or by the nfs:/ kioslave in KDE. The default is to use privileged ports.
rw The client will have read and write access to the exported directory. The default is to allow read-only access.
sync The server must wait until filesystem changes are committed to storage before responding to further client requests. This is the default.
no_subtree_check The server will not verify that a file requested by a client is in the appropriate filesystem and exported tree. This is the default.
crossmnt The server will reveal filesystems that are mounted under the virtual root directory that would otherwise be hidden when a client mounts the virtual root directory.
fsid=0 This option is required to uniquely identify the virtual root directory.

If changes are made to /etc/exports after the NFS server has started, issue the following command to propagate the changes to clients:

root #exportfs -rv
Even though the contrary is written in a lot of places, it is also possible to directly export the required directory, without creating a virtual root:
FILE /etc/exports
Multiple IP addresses

To add extra interfaces or IP addresses to the shares already configured, add the them to the corresponding line in /etc/exports. Below is a sample configuration using a local IPV6 address.

FILE /etc/exports
/export,rw,sync,no_subtree_check,crossmnt,fsid=0) 2000:aabb:ccdd:a::/64(insecure,rw,sync,no_subtree_check,crossmnt,fsid=0)
/export/home,rw,sync,no_subtree_check) 2000:aabb:ccdd:a::/64(insecure,rw,sync,no_subtree_check)
/export/data,rw,sync,no_subtree_check) 2000:aabb:ccdd:a::/64(insecure,rw,sync,no_subtree_check)

Different client options can be defined for each each IP address/interface.



The NFS daemon on OpenRC is configured via the OPTS_RPC_NFSD variable:

FILE /etc/conf.d/nfs
OPTS_RPC_NFSD="8 -N 2 -V 3 -V 4 -V 4.1"

The NFS daemon on systemd is configured via the RPCNFSDARGS variable:

FILE /etc/conf.d/nfs
RPCNFSDARGS="8 -N 2 -V 3 -V 4 -V 4.1"

The option 8 is the number of NFS server threads to start. Since only one thread is started by default, the thread count should be increased for optimal performance. The option -N 2 disables NFS version 2, while options -V 3, -V 4 and -V 4.1 enable NFS versions 3, 4, and 4.1. Refer to man nfsd for more information about the NFS daemon configuration options.



To start the NFS server:

root #/etc/init.d/nfs start
 * Starting rpcbind ...                                                   [ ok ]
 * Starting NFS statd ...                                                 [ ok ]
 * Starting idmapd ...                                                    [ ok ]
 * Exporting NFS directories ...                                          [ ok ]
 * Starting NFS mountd ...                                                [ ok ]
 * Starting NFS daemon ...                                                [ ok ]
 * Starting NFS smnotify ...                                              [ ok ]

The above output shows that many other services are also started along with the nfs service. To stop all NFS services, stop the rpcbind service:

root #rc-service rpcbind stop

To start the NFS server at boot:

root #rc-update add nfs default


To start the NFS server:

root #systemctl start rpcbind nfs-server

To start the NFS server at boot:

root #systemctl enable rpcbind nfs-server




To be able to mount exported directories, start the NFS client:

root #rc-service nfsclient start
 * Starting rpcbind                                                       [ ok ]
 * Starting NFS statd                                                     [ ok ]
 * Starting NFS sm-notify                                                 [ ok ]

To start the NFS client at boot:

root #rc-update add nfsclient default


The nfs-client service will be started automatically when systemd detects that exported directories are being mounted.

Mounting exports

The commands and configuration files below use the IP address to represent the NFS server.

Mount the exported directories:

root #mount /home
root #mount /data

To make the above mounts persistent, add the following to /etc/fstab:

FILE /etc/fstab    /home    nfs    rw,_netdev    0    0    /data    nfs    rw,_netdev    0    0

The virtual root directory can be mounted instead of each individual exported directory. This will make all exported directories available to the client:

root #mount /mnt

To make the above mount persistent, add the following to /etc/fstab:

FILE /etc/fstab        /mnt     nfs    rw,_netdev    0    0

When using /etc/fstab to mount the exported directories, add the netmount service to the default runlevel:

root #rc-update add netmount default
It will probably be necessary to specify the network management dependencies in /etc/conf.d/netmount.

If the NFS server or client support NFSv3 only, the full path to the exported directory (e.g. /export/home or /export/data) needs to be specified when mounting:

root #mount /home
root #mount /data

The same applies when mounting the virtual root directory:

root #mount /mnt

When mounting exported directories on an IPv6 network, enclose the IPv6 NFS server address in square brackets:

root #mount [2001::215:c5ff:fb3e:e2b1]:/home /home
root #mount [2001::215:c5ff:fb3e:e2b1]:/data /data

When mounting a link-local IPv6 address, the network interface must also be specified:

root #mount [fe80::215:c5ff:fb3e:e2b1%eth0]:/home /home
root #mount [fe80::215:c5ff:fb3e:e2b1%eth0]:/data /data

With NFSv4, the virtual root directory is rather 'invisible'; use relative path:

root #mount -t nfs4 /home
root #mount -t nfs4 /data


It is possible to identify NFS client using Kerberos GSS. This will require a few modifications. In the following instruction, it is supposed that Kerberos is already installed on the same server as NFS (which hostname is server.domain.tld) and that the client (client.domain.tld) is able to kinit to it. The Kerberos default realm it DOMAIN_REALM.TLD.

First, enable the following kernel option (CONFIG_RPCSEC_GSS_KRB5) for both server and client. Note that this option may not appear if all cryptographic dependencies are not selected. See kernel option dependencies for more information:

KERNEL Enabling Keberos for RPC
File systems --->
  [*] Network File Systems --->
        <*>   Secure RPC: Kerberos V mechanism

Then, create principals for the NFS service for both the server and the client. On the server, execute:

root #kadmin.local add_principal -randkey nfs/server.domain.tld
root #kadmin.local add_principal -randkey nfs/client.domain.tld

Each computer must have its password saved in a local keytab. The easiest way to do it is (on the server):

root #kadmin.local ktadd nfs/server.domain.tld
root #kadmin.local ktadd -k /root/krb5.keytab nfs/client.domain.tld

and then transfer the /root/krb5.keytab to the client, with the name /etc/krb5.keytab. Note that the file should be owned by root with 0600 mode.

The service rpc.gssd must run at client side. The following line must appear in /etc/conf.d/nfsclient of the client:

FILE /etc/conf.d/nfsclient
rc_need="!rpc.statd rpc.gssd"

The services rpc.idmapd and rpc.svcgssd must run at server side. The following line must appear in /etc/conf.d/nfs of the server:

FILE /etc/conf.d/nfs
NFS_NEEDED_SERVICES="rpc.idmapd rpc.svcgssd"

The rpc.idmapd service must be correctly configured (on the server):

FILE /etc/idmapd.conf

Domain = domain.tld

Add sec=krb5 to the export options.

FILE /etc/exports

It is also possible to increase security with sec=krb5i (user authentication and integrity checking) or even sec=krb5p (user authentication, integrity checking and NFS traffic encryption). The more security, the more resources are needed.

The same option must be added to the mount command at client side.


  • The system may become unresponsive during shutdown when the NFS client attempts to unmount exported directories after udev has stopped. To prevent this issue, a local.d script can be used to forcibly unmount the exported directories during shutdown:
FILE /etc/local.d/nfs.stop
/bin/umount -a -f -t nfs,nfs4
root #chmod a+x /etc/local.d/nfs.stop
  • Verify that the NFS server is running and listening for connections:
root #netstat -tupan | egrep 'rpc|Active|Proto'
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 *               LISTEN      1891/rpc.statd
tcp        0      0   *               LISTEN      1875/rpcbind
udp        0      0   *                           1875/rpcbind
udp        0      0 *                           1891/rpc.statd
udp        0      0   *                           1875/rpcbind
udp        0      0   *                           1891/rpc.statd
  • Verify which NFS daemons are running:
root #rpcinfo -p
   program vers proto   port  service
    100000    4   tcp    111  portmapper
    100000    3   tcp    111  portmapper
    100000    2   tcp    111  portmapper
    100000    4   udp    111  portmapper
    100000    3   udp    111  portmapper
    100000    2   udp    111  portmapper
    100024    1   udp  57655  status
    100024    1   tcp  34950  status
    100003    2   tcp   2049  nfs
    100003    3   tcp   2049  nfs
    100003    4   tcp   2049  nfs
    100003    2   udp   2049  nfs
    100003    3   udp   2049  nfs
    100003    4   udp   2049  nfs
    100021    1   udp  44208  nlockmgr
    100021    3   udp  44208  nlockmgr
    100021    4   udp  44208  nlockmgr
    100021    1   tcp  44043  nlockmgr
    100021    3   tcp  44043  nlockmgr
    100021    4   tcp  44043  nlockmgr
  • List the exported directories from the NFS server:
root #exportfs -v
  • List the current open connections to the NFS server:
user $netstat -tn | egrep '2049|Active|Proto'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0        ESTABLISHED
  • Verify that the exported directories are mounted by the NFS client:
user $netstat -tn | egrep '2049|Active|Proto'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0        ESTABLISHED

See also

  • Samba — a re-implementation of the SMB/CIFS networking protocol, a Microsoft Windows alternative to Network File System (NFS).

External resources