can you (theoretically) run only NFSv4 (without earlier versions)?

Tom H tomh0665 at
Tue Dec 24 09:21:59 UTC 2013

On Tue, Dec 24, 2013 at 2:10 AM, Ed Greshko <Ed.Greshko at> wrote:
> On 12/24/13 09:12, Robert P. J. Day wrote:
> After making the suggested changes.....
> [root at meimei ~]# mount -o ro,nfsvers=4 /mnt
> [root at meimei ~]# mount | grep mnt
> on /mnt type nfs4 (ro,relatime,vers=4.0,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=,local_lock=none,addr=
> [root at meimei ~]# umount /mnt
> [root at meimei ~]# mount -o ro,nfsvers=3 /mnt
> mount.nfs: requested NFS version or transport protocol is not supported

I tried disallowing v2 and v3 on Fedora 19 and failed.

"cat /proc/fs/nfsd/versions" shows that v2 and v3 are allowed by the
kernel and "mount -t -o nfsvers=3 ..." succeeds.

I ssh'd into a RHEL 6 box and an Ubuntu 14.04 VM where I know that v2
and v3 are disabled.

"cat /proc/fs/nfsd/versions" shows that v2 and v3 are disallowed and
"mount -t -o nfsvers=3 ..." fails.

I must've done something wrong on Fedora 19. I'll have to try again
later, but I can't see anything wrong in my setup offhand.

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