[Samba] Print server communications back to the client during printing

[Jeremy Allison]

On Mon, Oct 13, 2008 at 01:39:30PM -0400, Ryan Novosielski wrote:
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> Jeremy Allison wrote:
> > On Mon, Oct 13, 2008 at 11:57:45AM -0400, Gerald (Jerry) Carter wrote:
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> >> Taylor, Marc wrote:
> >>> Hello All,
> >>>
> >>> I was wondering if anyone knows why a print server needs to talk back on
> >>> the submitting client's ports 139 or 445?
> >> It's Microsoft's async print change notification protocol.  Jeremy
> >> had talked about adding a separate timetou for the back channel connect,
> >> but I don't remember if this was ever done.
> > 
> > Like the man said, it's Microsoft's doing :-). No, we don't have
> > a separate timeout in spoolss_connect_to_client()
> > (rpc_server/srv_spoolss_nt.c) but we could add one.
> 
> How does this actually work in the case of Samba? Does the Samba server
> attempt to contact the NT machine, and is there a benefit to allowing
> this to happen?

We do *exactly* what the Windows server does. Yes, we attemt to contact
the Windows client, as that's what Windows does. The benefit is it
correctly implements the Windows printing change-notify protocol.

Jeremy.