Can't mount a Windows share using the mount.cifs vers= option on SLES 11

This document (7018804) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 11 SP4
SUSE Linux Enterprise Server 11 SP3
SUSE Linux Enterprise Server 11 SP2
SUSE Linux Enterprise Server 11 SP1

Situation

Unable to mount a Windows share using the mount command on SLES11 with the vers=2.0 option.
The Windows server has been configured to only allow SMBv2.

If the Windows server is configured to allow SMBv1 the mount command works regardless of the presence of the vers= option.

Resolution

Use a version of SLES with a 3.5 or later kernel or configure the Windows server to allow SMBv1.

SLES12 would be an example of a version of the SLES OS that has a kernel version that is later than 3.5 which does have the vers= option.

Cause

On SLES 11 kernel's the cifs client code does not have support for the vers= option.

The vers= option is available on SLES in kernels that are later than 3.5.

On SLES 11 the kernel's mount command doesn't actually error out on its own when this option is used but simply ignores the option and sends SMBv1 headers.

When the Windows server is configured to not allow SMBv1 the Windows server will send a TCP RST to the Negotiate Protocol Request sent from the SLES server with an SMBv1 header. This is to be expected.

This TCP RST results in an error like this being seen at the console:
mount error (112): Host is down
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

Additional Information

smbclient fails after disabling SMBv1 on Windows server
https://www.suse.com/support/kb/doc.php?id=7019892

Disclaimer

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