[Samba] NetBIOS called name not sent using smbclient 4.0.9 and CUPS 1.6.3

Pol Van Aubel dev at polvanaubel.com
Fri Sep 27 12:09:40 MDT 2013

I suspect a bug in either smbclient 4.0.9 or CUPS 1.6.3 (which wouldn't
be Samba's problem, of course) where a linux client does not send the
server's Called Name in the NetBIOS session request sent to a server
using smb. Now, the problem is that my university's print system selects
the print configuration file to use based on matching the Called Name.
No Called Name leads to no configuration and no printing.

Attached are two packet captures for access to the same print server
from two different machines.

One session, capture-printsmb-ubuntu-filtered.pcap, clearly sends
PRINTSMB.SCIENC as Called Name (packet 10). This is using CUPS 1.6.2 and
smbclient 3.6.9 on an Ubuntu 13.04 installation.

The other session, capture-printsmb-1-filtered.pcap, has an empty field
(repeating bytes 0xCA) at that location. This is using CUPS 1.6.3 and
smbclient 4.0.9 on an (up-to-date) Arch linux installation.

The DeviceURI used for this printer is

The server's administrators and I have established (and it can be seen
in the packet captures) that the machine is being reached, and that the
only difference really is with the NetBIOS session request.

Now, either the problem is with CUPS, or rather, how CUPS calls
smbclient and what information is passed along, or it is with smbclient
itself. Because of this, I'm also sending this e-mail to the OSX
Printing List (because the CUPS lists themselves are down right now),
and hope we can reach a conclusion of why this is happening, and whether
it should be fixed.


Pol Van Aubel

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