Check active NFS connections

Is it possible to view active NFS/RPC connections to a server? It's a
simple task on the client to just cat mtab. At least, that the
*easiest* way. I'd like to be able to look on the server though and
determine if not which clients are connected at least how many there
are.

Thanks
Mathew

(E-Mail Removed) wrote:
> Is it possible to view active NFS/RPC connections to a server? It's a
> simple task on the client to just cat mtab. At least, that the
> *easiest* way. I'd like to be able to look on the server though and
> determine if not which clients are connected at least how many there
> are.

showmount -a (on the server)
Chris

Chris Davies wrote:

>> Is it possible to view active NFS/RPC connections to a server? It's a
>> simple task on the client to just cat mtab. At least, that the
>> *easiest* way. I'd like to be able to look on the server though and
>> determine if not which clients are connected at least how many there
>> are.
>
> showmount -a (on the server)

I hadn't heard of this command.
When I run it I seem to get every computer connected to my server
by WiFi or ethernet, as seen below.
What exactly do the 255.255.255.0 directory entries mean?

--------------------------------
[tim@alfred ~]$ showmount -a
All mount points on alfred.murphy.ie:
192.168.2.0/255.255.255.0:/common
192.168.2.11:192.168.2.0/255.255.255.0
192.168.2.14:192.168.2.0/255.255.255.0
192.168.2.234:192.168.2.0/255.255.255.0
192.168.2.235:192.168.2.0/255.255.255.0
192.168.2.4:192.168.2.0/255.255.255.0
192.168.2.6:192.168.2.0/255.255.255.0
192.168.2.7:192.168.2.0/255.255.255.0
192.168.3.0/255.255.255.0:/common
192.168.3.11:192.168.3.0/255.255.255.0
192.168.3.2:192.168.3.0/255.255.255.0
192.168.3.6:192.168.3.0/255.255.255.0
--------------------------------

--
Timothy Murphy
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

Timothy Murphy wrote:
> Chris Davies wrote:
>
>>> Is it possible to view active NFS/RPC connections to a server? It's a
>>> simple task on the client to just cat mtab. At least, that the
>>> *easiest* way. I'd like to be able to look on the server though and
>>> determine if not which clients are connected at least how many there
>>> are.
>> showmount -a (on the server)
>
> I hadn't heard of this command.
> When I run it I seem to get every computer connected to my server
> by WiFi or ethernet, as seen below.
> What exactly do the 255.255.255.0 directory entries mean?
>
> --------------------------------
> [tim@alfred ~]$ showmount -a
> All mount points on alfred.murphy.ie:
> 192.168.2.0/255.255.255.0:/common
> 192.168.2.11:192.168.2.0/255.255.255.0
> 192.168.2.14:192.168.2.0/255.255.255.0
> 192.168.2.234:192.168.2.0/255.255.255.0
> 192.168.2.235:192.168.2.0/255.255.255.0
> 192.168.2.4:192.168.2.0/255.255.255.0
> 192.168.2.6:192.168.2.0/255.255.255.0
> 192.168.2.7:192.168.2.0/255.255.255.0
> 192.168.3.0/255.255.255.0:/common
> 192.168.3.11:192.168.3.0/255.255.255.0
> 192.168.3.2:192.168.3.0/255.255.255.0
> 192.168.3.6:192.168.3.0/255.255.255.0
> --------------------------------
>

Unfortunately showmount shows everything that EVER mounted, not what's
currently mounted. Fairly useless if you ask me. I don't know of any
better alternatives

Joe Beanfish wrote:

>
> Unfortunately showmount shows everything that EVER mounted, not what's
> currently mounted. Fairly useless if you ask me. I don't know of any
> better alternatives

I was about to chip in earlier with "NFS is a stateless protocol" so it's
hard.

However, if the OP runs NFS over TCP, rather than UDP, the he could look for
stuff like the following with "netstat -apl | grep nfs" :


tcp 0 0 mothra.dionic.net:nfs genghis.dionic.net:792 ESTABLISHED-

Probably about as good as it gets.


Cheers

Tim

PS - sorry for replying to you, my newsreader lost its cache so I don't have
the earlier article...

> Is it possible to view active NFS/RPC connections to a server?

Chris Davies wrote:
> showmount -a (on the server)

Timothy Murphy <(E-Mail Removed)> wrote:
> When I run it I seem to get every computer connected to my server

None of these systems ever unmounted the directory. Since NFS is a
stateless protocol (well, mostly) it's impossible for the server to
distinguish between a client that's just not using the mount and one
that's gone away and forgotten about it.

Chris

Chris Davies wrote:

>> Is it possible to view active NFS/RPC connections to a server?
>
> Chris Davies wrote:
>> showmount -a (on the server)
>
> Timothy Murphy <(E-Mail Removed)> wrote:
>> When I run it I seem to get every computer connected to my server
>
> None of these systems ever unmounted the directory. Since NFS is a
> stateless protocol (well, mostly) it's impossible for the server to
> distinguish between a client that's just not using the mount and one
> that's gone away and forgotten about it.

I still don't understand the output of "showmount -a" (below).

I just rebooted the NFS server (alfred).
Most of the computers listed are not switched on,
or are not running Linux,
and have never mounted a directory on the server.

As far as I can see, if one computer on a LAN
has a directory on the server mounted
then all other computers which are on the LAN,
or have been on the LAN in the last n weeks,
are listed.

Is this normal?
It is quite possible that my NFS setup is faulty in some way,
though as far as I know it is completely standard.

------------------------
[tim@elizabeth ~]$ sudo showmount -a alfred
All mount points on alfred:
192.168.2.0/255.255.255.0:/common
192.168.2.11:192.168.2.0/255.255.255.0
192.168.2.14:192.168.2.0/255.255.255.0
192.168.2.234:192.168.2.0/255.255.255.0
192.168.2.235:192.168.2.0/255.255.255.0
192.168.2.4:192.168.2.0/255.255.255.0
192.168.2.6:192.168.2.0/255.255.255.0
192.168.2.7:192.168.2.0/255.255.255.0
192.168.3.0/255.255.255.0:/common
192.168.3.11:192.168.3.0/255.255.255.0
192.168.3.2:192.168.3.0/255.255.255.0
192.168.3.6:192.168.3.0/255.255.255.0
------------------------

--
Timothy Murphy
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

Timothy Murphy wrote:
> Chris Davies wrote:
>
>>> Is it possible to view active NFS/RPC connections to a server?
>> Chris Davies wrote:
>>> showmount -a (on the server)
>> Timothy Murphy <(E-Mail Removed)> wrote:
>>> When I run it I seem to get every computer connected to my server
>> None of these systems ever unmounted the directory. Since NFS is a
>> stateless protocol (well, mostly) it's impossible for the server to
>> distinguish between a client that's just not using the mount and one
>> that's gone away and forgotten about it.
>
> I still don't understand the output of "showmount -a" (below).

showmount -a is not useful. Forget it exists.