How to set NFS server on version 3 (only)

hcvv · March 20, 2026, 11:36am

I upgraded my NFS server system 15.6 > 16.0. Now the NFS client can not mount the export from it.

On the server:

boven:/etc/nfs.conf.d # cat /etc/exports
/home/wij       *.henm.xs4all.nl(rw,no_root_squash,sync,no_subtree_check)
boven:/etc/nfs.conf.d # 

boven:/etc/nfs.conf.d # systemctl status nfs-server.service 
● nfs-server.service - NFS server and services
     Loaded: loaded (/usr/lib/systemd/system/nfs-server.service; enabled; preset: disabled)
    Drop-In: /usr/lib/systemd/system/nfs-server.service.d
             └─10-options.conf
             /run/systemd/generator/nfs-server.service.d
             └─order-with-mounts.conf
     Active: active (exited) since Fri 2026-03-20 10:38:55 CET; 1h 43min ago
 Invocation: bb9e26da1c2240abbeee0ed7cd35e156
       Docs: man:rpc.nfsd(8)
             man:exportfs(8)
    Process: 12479 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=0/SUCCESS)
    Process: 12480 ExecStart=/usr/sbin/rpc.nfsd $NFSD_OPTIONS (code=exited, status=0/SUCCESS)
   Main PID: 12480 (code=exited, status=0/SUCCESS)
        CPU: 16ms

Mar 20 10:38:55 boven systemd[1]: Starting NFS server and services...
Mar 20 10:38:55 boven systemd[1]: Finished NFS server and services.
boven:/etc/nfs.conf.d #

And surprisingly also

boven:/etc/nfs.conf.d # systemctl status nfsdcld.service 
● nfsdcld.service - NFSv4 Client Tracking Daemon
     Loaded: loaded (/usr/lib/systemd/system/nfsdcld.service; static)
     Active: active (running) since Fri 2026-03-20 10:43:09 CET; 1h 40min ago
 Invocation: f2945725a02f4f689f4f10af2eb9dd82
       Docs: man:nfsdcld(8)
    Process: 12800 ExecStart=/usr/sbin/nfsdcld (code=exited, status=0/SUCCESS)
   Main PID: 12801 (nfsdcld)
      Tasks: 1 (limit: 9219)
        CPU: 8ms
     CGroup: /system.slice/nfsdcld.service
             └─12801 /usr/sbin/nfsdcld

Mar 20 10:43:09 boven systemd[1]: Starting NFSv4 Client Tracking Daemon...
Mar 20 10:43:09 boven systemd[1]: Started NFSv4 Client Tracking Daemon.
boven:/etc/nfs.conf.d #

which I guess means that NFS version 4 is served.

To force both systems to Version3, I added on the client the version= option:

beneden:~ # grep nfs /etc/fstab
boven.henm.xs4all.nl:/home/wij             /home/wij  nfs   nfsvers=3,noauto,nofail,x-systemd.automount,x-systemd.mount-timeout=10,x-systemd.idle-timeout=5min  0  0
beneden:~ #

Now I want to force the server to also use Version3 (when possible only).

The configuration files seem to have changed a lot since 15.6. THe old /etc/sysconfig/nfs had (snippet):

# Enable NFSv3 server support (yes/no)
# This causes the NFS server to respond to
# NFSv2 and NFSv3 requests.  Only disable this
# if you want to ensure only NFSv4 is used.
#
NFS3_SERVER_SUPPORT="yes"

## Path:                Network/File systems/NFS server
## Description:         NFSv4 protocol support
## Type:                yesno
## Default:             yes
## ServiceRestart:      nfs-server
#
# Enable NFSv4 support (server and/or client) (yes/no)
#
NFS4_SUPPORT="no"

New files are:

/usr/etc/nfs.conf
/usr/etc/nfs.conf.d/.conf
/etc/nfs.conf
/etc/nfs.conf.d/.conf
Various configuration files read in order. Later settings override earlier settings.

and have sections.

Thus I created the following:

boven:/etc/nfs.conf.d # cat version-override.conf 
[nfsd]
 vers3=y
 vers4=n

boven:/etc/nfs.conf.d #

After restarting nfs-server it is still the same: nfsdcld still running and no mounting on the client.

Has anybody any experience with this. TIA.

knurpht · March 20, 2026, 11:52am

How? Would be good to know.

hcvv · March 20, 2026, 12:06pm

Changed the repo list (removed all and added the three named in doc) and basically zypper --releasever 16.0 dup --allow-vendorchange. Worked pretty well.

boven:/etc/nfs.conf.d # zypper lr -d
# | Alias   | Name           | Enabled | GPG Check | Refresh | Keep | Priority | Type   | URI                                                                     | Service
--+---------+----------------+---------+-----------+---------+------+----------+--------+-------------------------------------------------------------------------+--------
1 | non-oss | Main (Non-OSS) | Yes     | (r ) Yes  | Yes     | -    |   99     | rpm-md | http://download.opensuse.org/distribution/leap/16.0/repo/non-oss/x86_64 | 
2 | open264 | open264 codecs | Yes     | (r ) Yes  | Yes     | -    |   99     | rpm-md | http://codecs.opensuse.org/openh264/openSUSE_Leap_16/                   | 
3 | oss     | Main (OSS)     | Yes     | (r ) Yes  | Yes     | -    |   99     | rpm-md | http://download.opensuse.org/distribution/leap/16.0/repo/oss/x86_64     | 
boven:/etc/nfs.conf.d #

rawar · March 20, 2026, 12:49pm

On my Leap 16.0 server (new installation not migrated) NFS 3 is enabled by default. Please post :

# cat /proc/fs/nfsd/versions
-2 +3 +4 +4.1 +4.2

hcvv · March 20, 2026, 1:00pm

boven:/etc # cat /proc/fs/nfsd/versions
-2 +3 -4 -4.0 -4.1 -4.2
boven:/etc #

That looks like only version 3 is used. But why is then still that nfsdcld running. Which is of course a minor problem compaired with: why can’t the client mount the export.

rawar · March 20, 2026, 1:03pm

Just a guess firewall ?

# firewall-cmd --list-all|grep services
  services: cockpit dhcpv6-client mountd nfs nfs3 rpc-bind ssh

hcvv · March 20, 2026, 1:07pm

I have no firewall running on both systems.

STOP PRESSES:

boven:/etc # firewall-cmd --list-all|grep services
  services: dhcpv6-client ssh
boven:/etc # ps -ef | grep firewalld/
root       30432    6366  0 14:05 pts/0    00:00:00 grep --color=auto firewalld/
boven:/etc # ps -ef | grep firewal
root         955       1  0 08:23 ?        00:00:00 /usr/bin/python3.13 /usr/sbin/firewalld --nofork --nopid
root       30451    6366  0 14:05 pts/0    00:00:00 grep --color=auto firewal
boven:/etc # systemctl status firewalld.service 
● firewalld.service - firewalld - dynamic firewall daemon
     Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; preset: enabled)
     Active: active (running) since Fri 2026-03-20 08:23:55 CET; 5h 41min ago
 Invocation: 2b90da87403747178dfbb993a97fc0c9
       Docs: man:firewalld(1)
   Main PID: 955 (firewalld)
      Tasks: 2 (limit: 9219)
        CPU: 891ms
     CGroup: /system.slice/firewalld.service
             └─955 /usr/bin/python3.13 /usr/sbin/firewalld --nofork --nopid

Mar 20 08:23:53 boven systemd[1]: Starting firewalld - dynamic firewall daemon...
Mar 20 08:23:55 boven systemd[1]: Started firewalld - dynamic firewall daemon.
boven:/etc # systemctl stop firewalld.service

It was switched on!. I never have one running, thus I did not expect that the upgrade switched it on.

I will no try again and report back.

hcvv · March 20, 2026, 1:11pm

That is it. All is working to satisfaction now.

I would never have thought of the firewall. I never used it for many years.

Thanks you for walking a different path of thought and thus finding the culprit.

(And I am wondering while the upgrade does this )

system · March 27, 2026, 1:12pm

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