[linux-cifs-client] use non-zero vcnumbers patch

Christopher R. Hertel crh at ubiqx.mn.org
Wed Feb 4 04:13:58 GMT 2009


Steve French wrote:
> In the situation you describe - I thought that the server could
> recognize that they are distinct sockets, and source ports, but
> perhaps with Win9x didn't

I'll have to test this behavior again, just to see.  I *think* I was testing
smbclient and jCIFS simultaneously against W2K when I ran into it years ago.

Here's that KB article I mentioned:
  http://support.microsoft.com/default.aspx?scid=KB;en-us;301673

Curious...  It says NT4 servers don't have this problem.  I'll have to check
that too.  :)

Here's what I wrote about VCs 7 or 8 years ago:
  http://www.ubiqx.org/cifs/SMB.html#SMB.7.1.1

The problem is that there's theory and there's practice.  I think of the
whole VC thing as a vestigial organ, like an appendix.  It isn't used much
any more, so how it actually works in any give implementation depends...

Chris -)-----

> On Tue, Feb 3, 2009 at 9:19 PM, Christopher R. Hertel <crh at ubiqx.mn.org> wrote:
>> Steve French wrote:
>> :
>>> I also remember the old situation that Chris H. mentions about vc
>>> numbers and NATs and the nasty behavior change it required.
>> NATs, and multiple connections from a single machine.  Say someone has (for
>> example) an smbclient session open and then mounts a share using CIFS.  If
>> CIFS sends VC=0 the smbclient session may be dropped.
>>
>> As I recall (haven't tested lately) newer Windows servers no longer drop
>> existing connections if a new VC=0 connection comes in.  If that is the
>> case, then there's no point in sending VC=0 anyway.
>>
>> Again, I'm going from memory so I could be wrong here, but I think jCIFS
>> sends VC=1 for all connections and doesn't have a problem.  Two TCP
>> connections from the same client with the same VC number would (assuming the
>> old OS/2 idea of a VC is supported) be seen as a single virtual circuit over
>> two physical circuits.
>>
>> Chris -)-----
>>
>> --
>> "Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
>> Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
>> jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development, uninq.
>> ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
>> OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org
>>
> 
> 
> 

-- 
"Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development, uninq.
ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org


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