cifs client question: a cifs mount to a z/OS mainframe server

Nadezhda Ivanova nivanova at
Mon Apr 7 06:02:58 MDT 2014

Hi David,
They are running 3.11.0-19-generic. The nosharesock option is accepted, but
it does not solve the problem. I will send the user commands, software
versions and wireshark caps showing the malformed packet to the cifs.ko
list, is that the linux-cifs at


On Mon, Apr 7, 2014 at 2:22 PM, David Disseldorp <ddiss at> wrote:

> Hi Nadezhda,
> On Sun, 6 Apr 2014 17:33:43 +0300, Nadezhda Ivanova wrote:
> > Hi guys,
> > Has anyone managed to make a mount.cifs mount from a linux machine to a
> > share on a z/OS IBM Mainframe? We have a partner that is trying to do
> that,
> > but the the z/OS returns a malformed Negotiate Protocol Response packet,
> > incorrect bcc caused by PRIMARY DOMAIN containing garbage. Interestingly,
> > the mount is successful from a Windows or a mac, and the z/OS returns a
> > correct packet to these clients. Any ideas?
> What kernel version is the client running?
> The symptoms don't appear to match what you've reported, but we've seen
> issues against IBM servers when the cifs.ko client exceeds the servers
> MaxNumberVCs value during login.
> The nosharesock mount option was recently added to avoid this behaviour.
> I'd suggest taking this up on the cifs.ko mailing list.
> Cheers, David

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