smbclient -M : big delays

Anders C. Thorsen anders at
Tue Apr 2 06:56:02 GMT 2002

Atleast long delays is a problem using NET SEND between two Windows 2000 and 
Win2k to WinXP computers that are not part of the same domain (no trust 

This occurrs even if the user sending the message authenticated to 
\\DESTINATION\IPC$ and are able to access shares on the othe computer. 

Between two Win2k clients within the same domain, the NET SEND command 
returns instantly. 

Perhaps this is some sort of measures taken on Microsoft's part to avoid 
"spamming" from non-authenticated clients? 


David Lee writes: 

> Back in the days of 2.2.1a, I noticed a problem using "smbclient -M" to
> send WinPopup messages from a server (Solaris 2.x) to a client (W2K).  But
> I was unable to pursue it at the time. 
> I have just started looking at this area again, using Samba 2.2.3a, and
> the problem still seems to be present. 
> Briefly, the symptom is a long delay (pushing 15 seconds) before the
> message is displayed on the client.  
> Looking more deeply (using "snoop" on the UNIX box to capture the network
> traffic), what is seen is:  
> 1. rapid exchange of about 6 packets as the session is established (fine). 
> 2. UNIX (smbclient) sends "SMBsendstrt" quickly.
>    -- total elapsed time so far about 0.3 seconds (fine) 
> 3. big delay (~ 5 seconds) before client (W2k) returns the SMBsendstrt
>    acknowledgement (problem). 
> 4. rapid UNIX turnaround to send "SMBsendtxt" (fine). 
> 5. big delay before client (W2K) acknowledges "SMBsendtxt" (problem) 
> 6. rapid UNIX turnaround to send "SMBsendend" (fine) 
> 7. big delay before client (W2K) acknowledges "SMBsendend" (problem). 
> At first sight, the problem appears to lie at the PC/client end, waiting
> nearly five seconds before acknowledging each of the "SMBsend*" that had
> come from the UNIX/server.  
> Might this be this a known PC/client/W2K problem?  (Testing with non-W2K
> client-types would be trickly, but possibly do-able if necessary.) 
> Or is it actually a Samba problem?  (For instance, are the "SMBsend*" 
> packets improperly constructed (e.g. (speculative) not pushed), leading
> the PC/client to believe that the packet is, for instance, incomplete.) 
> I've got no experience of programming at the SMB level, so am somewhat
> lost. 
> But if anyone can reproduce it, and if anyone can help pursue it, I can
> provide the UNIX "snoop" output. 
> --  
> :  David Lee                                I.T. Service          :
> :  Systems Programmer                       Computer Centre       :
> :                                           University of Durham  :
> :            South Road            :
> :                                           Durham                :
> :  Phone: +44 191 374 2882                  U.K.                  : 

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