samba - Dec 2025 - Xubuntu LTS upgrade from 22.04 to 24.04 seems to have broken Samba NT4 PDC mounting mount.cifs returns error(95): Operation not supported

Greetings,

We recently started upgrading from Xubuntu 22.04 to 24.04. It appears that
causes a break in our ability to logon / mount drive shares to our Samba NT4
style PDC.

We now (after the upgrade) receive:

mount error(95): Operation not supported
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) and kernel log
messages (dmesg)



Command line is as follows:

mount.cifs //cirlnx01/data /mnt/cirlnx01/data -o
credentials=/home/mdlueck/.smbcredentials,uid=mdlueck,gid=mdlueck,dir_mode=0777,file_mode=0666,nobrl,vers=1.0


I have not been able to find a way to get the updated version of mount.cifs to
continue successfully mounting to our Samba NT4 style PDC.

A while ago we had to add the "vers=1.0" to keep things working.

Aggravating that adjustments to the Samba code done breaks working legacy
syntax. I scratch my head how suddenly "vers=1.0" is not compatible
with the stable Samba NT4 style PDC.

Suggestions? We appreciate.

I am thankful,

-- 
Michael Lueck
Lueck Data Systems
http://www.lueckdatasystems.com/

Greetings again,

Apparently Linux client to Linux server, Samba to Samba, might be able to
successfully use higher protocol versions. I was suggested to try updating
"vers=1.0" to something higher, and it appears to
work from Xubuntu 24.04 client.

Asking again here....

Running a Samba server that is at 4.15.13 version, how high would it be safe to
set the Linux client "vers=" value to?

I am thankful,


Michael Lueck wrote:
> Greetings,
> 
> We recently started upgrading from Xubuntu 22.04 to 24.04. It appears that
causes a break in our ability to logon / mount drive shares to our Samba NT4
style PDC.
> 
> We now (after the upgrade) receive:
> 
> mount error(95): Operation not supported
> Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) and kernel log
messages (dmesg)
> 
> 
> 
> Command line is as follows:
> 
> mount.cifs //cirlnx01/data /mnt/cirlnx01/data -o
credentials=/home/mdlueck/.smbcredentials,uid=mdlueck,gid=mdlueck,dir_mode=0777,file_mode=0666,nobrl,vers=1.0
> 
> 
> I have not been able to find a way to get the updated version of mount.cifs
to continue successfully mounting to our Samba NT4 style PDC.
> 
> A while ago we had to add the "vers=1.0" to keep things working.
> 
> Aggravating that adjustments to the Samba code done breaks working legacy
syntax. I scratch my head how suddenly "vers=1.0" is not compatible
with the stable Samba NT4 style PDC.
> 
> Suggestions? We appreciate.
> 
> I am thankful,

-- 
Michael Lueck
Lueck Data Systems
http://www.lueckdatasystems.com/