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

[Tom H]

On Tue, Dec 24, 2013 at 12:15 AM, Robert P. J. Day
<rpjday at crashcourse.ca> wrote:
> Quoting Ed Greshko <Ed.Greshko at greshko.com>:
>>
>> In /etc/sysconfig/nfs
>>
>> # Optional arguments passed to rpc.nfsd. See rpc.nfsd(8)
>> RPCNFSDARGS=""
>>
>> man 8 rpc.nfsd
>>
>>       -N  or  --no-nfs-version vers
>>               This option can be used to request that rpc.nfsd does  not
>> offer
>>               certain versions of NFS. The current version of rpc.nfsd can
>> sup‐
>>               port NFS versions 2,3,4 and the newer version 4.1.
>
> i tried that and it didn't seem to work, in the sense that when i
> ran "rpcinfo -p" to verify the result, here's part of the output:
>
>     100003    3   tcp   2049  nfs
>     100227    3   tcp   2049  nfs_acl
>     100003    3   udp   2049  nfs
>     100227    3   udp   2049  nfs_acl
>     100003    4   tcp   2049  nfs
>     100003    4   udp   2049  nfs
>
> so isn't that telling me i still have both versions 3 and 4? here's
> the line i added to the file:
>
> RPCNFSDARGS="-N 2 -N 3"

1) Try "mount -t nfs -o nfsvers=3 ..."

2) cat /proc/fs/nfsd/versions