[cups] Mac as cupsclient

Michael Sweet msweet at apple.com
Fri Jan 20 06:01:05 PST 2017


> On Jan 20, 2017, at 5:07 AM, hw <hw at gc-24.de> wrote:
> 
> Michael Sweet schrieb:
>> First, the client.conf usage of ServerName has been deprecated for many years now - see the NOTES section of the man page. The recommended way to do printer sharing (since CUPS 1.0) is to use printer sharing and a local client queue for each printer.
> 
> Thank you very much for the detailed explanation!
> 
> How would I get a local client queue?  I do not want to install a full blown
> cups on each client.  I don´t want a local queue, either.

That's what you need, full CUPS (with cupsd).  There is no requirement to do local filtering (so you don't need local drivers, and in fact things work much better without them) but having the local cupsd decouples the application/client from the server.

>> The Mac implements application sandboxing, which means you cannot simply talk to any outside network service from a random application that would ordinarily not require access to the network.  Similar functionality is provided by AppArmor and SELinux...
> 
> Printer access usually requires network access.

There is a difference between talking directly to a network printer or server and talking to a local service (cupsd) which then manages communications with the printer.  The latter is explicitly allowed for all applications, while the former is not.

>> If you have Bonjour (Avahi) setup on your Linux CUPS server, you just need to pick the printer from the nearby printers list in the print dialog.  A local (pass-through) print queue will be setup on the Mac to talk to the CUPS server for that printer.
>> 
>> If you do not have Bonjour setup, you'll need to add each printer either from the Print & Scan preference pane (to enter the remote server and queue names) or the command-line using the lpadmin program (a common enough usage since you can provide a script to users that sets up the print queues once).
> 
> We have made the printers known to the Mac via samba.  There didn´t seem
> to be another way.

That's probably the worst way to print things since you are going through many levels of redirection just to get a raw print file on the CUPS server.

> The Mac seems to use its own drivers or whatever, and
> printing doesn´t work so well because there are all kinds of weird issues.
> It´s just a typical Mac where nothing really works.  I was hoping it might
> work if it could use the cups server as a client.

If you use Bonjour the Mac will use the driver on the CUPS server and those weird issues go away.

And FWIW, many drivers (including those on Linux!) need direct access to the printer when printing, so you'd run into the same problems printing from Linux over SMB or any other protocol with a local driver.

_________________________________________________________
Michael Sweet, Senior Printing System Engineer




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