[Samba] Printing: Request to make return connection to client optional samba 3.5.x

Volker Lendecke Volker.Lendecke at SerNet.DE
Fri Mar 18 09:19:58 MDT 2011

On Thu, Mar 17, 2011 at 10:57:41AM +0100, Urs Beckmann wrote:
> We have a network of Samba print-stations. There are complains from
> users of slow printing, which can be tracked to the
> return-connection which samba-server makes to print-client for
> dynamic update of printer-status. Since samba-servers are on
> different subnets than print-clients, the return-connection from
> samba to windows-client always fails in windows-firewall, but the
> tries to build up the return-connection lead to delay in printing
> and sometimes to delays in printer-properties dialog. It's not
> possible for us to ask clients to open their firewalls, we need a
> solution on print-server.
> What helps is to modify samba source as follows:
> in file rpc_server/srv_spoolss_nt.c:
> function spoolss_connect_to_client:
> do nothing but return False;
> Unfortunately a modified samba-version is not welcome here
> politically, so if this feature of optionally (configurable in
> smb.conf) not making the return-connection could be built into next
> version of samba in the 3.5.x line it would be very helpful.
> An other issue is the timeout for making a connection from Samba to
> the Windows DC for print authentication, fixed at 10 seconds, which
> is sometimes too small.
> This is in file libsmb/cliconnect.c:
> cli_set_timeout(cli, 10000); /* 10 seconds */
> If this timeout could optionally be increased to 30 seconds it would
> also be very helpful.

Does the attached patch help you? I've added patches for 3.5
and master. You should add "spoolss backchannel = no" to
your smb.conf [global] section to disable the backchannel
for all printers.

Please report if it solves your issue.

If you need that in 3.5.next, you should open a bug report
at https://bugzilla.samba.org.

With best regards,

Volker Lendecke

SerNet GmbH, Bahnhofsallee 1b, 37081 Göttingen
phone: +49-551-370000-0, fax: +49-551-370000-9
AG Göttingen, HRB 2816, GF: Dr. Johannes Loxen

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