[cifs-protocol] BKRP question/response

[Nick Meier]

Hi Matthieu,

* So basically there is no obligation for the client to try to downgrade from version 3 to version 2 right ?
	Correct - the client is not required to try a different version,
	and there are no requirements as to which version the client
	should try first.

* What is the behavior of the windows client ?
	Not sure, but we can look into this.

* Can you tell us the information if so can it be added as a behavior note ?
	Unlikely.  Windows behavior notes are for when Windows deviates
	from the protocol.  When we look into the previous question, if
	we find that Windows deviates from the protocol, we will add a
	behavior note.

	I spoke with Bryan and we can look into the possibility of documenting
	a high level description in a forum less formal than the protocol
	documents.  A blog or a KB article come to mind.

Based on my review of the document, if I was writing a client, I would implement both v2 and v3.  I would have the client try v3 first and then drop back to v2.  I would also allow for the disabling of one of the versions (but not both) for versatility/performance in known environments.

-Nick

-----Original Message-----
From: Matthieu Patou [mailto:mat at samba.org] 
Sent: Wednesday, September 29, 2010 11:11 AM
To: Nick Meier; cifs-protocol at samba.org
Subject: Re: BKRP question/response

  On 29/09/2010 20:45, Nick Meier wrote:
> Good Morning Matthieu,
>
> The follow are my findings after reviewing the MS-BKRP document.
>
> Question:
>      BKRP defines two version, v2 and v3.  If a server does not support the version requested by the client, how should the client behave?
>
> Assumptions:
>      Older versions of Windows support v2, newer versions of windows supports v2 and v3.
>
> Findings:
>      Section 3.1.4.1.4 provides a number of points.
>                  Point 2: If the dwVersion is not supported by the server, the server should return
>                                  ERROR_INVALID_PARAMETER
>                                  Also, the server must support at least one of the versions.
>
I read this from the server point of view.
> So, if a client tries one version and ERROR_INVALID_PARAMETER is returned, the client is free to try another version if the client supports multiple versions (and the alternate version is enabled on the client).
>
So basically there is no obligation for the client to try to downgrade from version 3 to version 2 right ? What is the behavior of the windows client ?
Can you tell us the information if so can it be added as a behavior note ?

Cheers.

Matthieu.


--
Matthieu Patou
Samba Team        http://samba.org