VCs, MaxNumberVCs, SessionKey

Richard Sharpe rsharpe at ns.aus.com
Fri Jun 28 10:15:02 GMT 2002


On Fri, 28 Jun 2002, Raghu Iyer wrote:

> Can a SMB expert help me understand how VcNumber, 
> MaxNumberVCs, SessionKey are used in the SMB protocol
> with some examples and commands that can be issued
> from a NT/W2K client to a NT/W2K/Samba Server to
> experiment with.

I dodn't think it is used, except with Terminal Server-like products.

It seems to have been an attempt to allow multiple security contexts over 
a single NBT session. However, it seems not well thought out, and you must 
be prepared to accept multiple SessSesup&X requests in anycase, and there 
is sufficient info in each SMB to keep this stuff separate (UID, MID, 
etc).
 
> Is there a good reference that can illustrate the concepts
> behind these parameters ? I have gone through the
> CIFS mailing list on discuss.microsoft.com and have a
> very hazy idea. I have not been able to produce sessions 
> where - MaxNumberVCs is > 1 OR where SessionKey 
> is != 0 OR where VcNumber is != 0. So I fail to appreciate
> under what circumstances these parameters change.

They are not discussed, except in passing, in CIFS-TR-1.0. If you do a 
goodle search on SMB VCnumber or some such, you will find some discussion.

If you or anyone can send some TerminalServer traces, it would be useful.

Regards
-----
Richard Sharpe, rsharpe at ns.aus.com, rsharpe at samba.org, 
sharpe at ethereal.com





More information about the samba-technical mailing list