samba - Mar 2011 - Printing: Request to make return connection to client optional samba 3.5.x

Hi
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.


Thank you
Urs Beckmann
ETH Z?rich, Informatikdienste, VPP
RZE25, Clausiusstr. 59, 8092 Z?rich
Tel 044 632 34 88, urs.beckmann at id.ethz.ch

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 G?ttingen
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