[cups] Fedora does not discover Printers

[Helge Blischke]

> Am 04.06.2016 um 09:24 schrieb Brett I. Holcomb <biholcomb at l1049h.com>:
> 
> I have a cups server running on Centos 7.2 (1511) and a client on
> Fedora 23 (several clients but I'm trying to get one working before I
> setup the others).  Both have cups installed and the Centos is setup as
> the cups server running cups 1.6.3 while Fedora has cups 2.1.3.  I have
> one network printer that the server has setup and can be printed to
> using the GUI test page.  I've setup share all printers on the server
> (at this point only the one).  
> 
> I've been beating my head against this for a couple of days trying to
> get cups to do what it is supposed to do and it's been frustrating.
> 
> What I want to do is have the client cups find the printers shared by
> the print servers on the network and allow them to be used by user
> applications.  The problem is that the Fedora client can not see the
> server's printer except under one condition I'll cover later.  
> 
> On the server I have this in the cupsd.conf
> 
> Browsing On
> BrowseLocalProtocols dnssd
> 
> <Location> has Allow all
> 
> I've run cupsctl --remote-any since my Fedora client is on a different
> subnet than the server.
> 
> On the client cupsd.conf which is as shipped
> 
> Browsing On
> BrowseLocalProtocols dnssd
> 
> The server is localhost.
> 
> I've spent the last few days researching as well as reading the cups
> documentation and haven't found anything that helps and at this point
> would gladly embrace an alternative to cups!  Supposedly cups on the
> client will locate the printers using discovery (ipp??, dnssd??) using
> the default settings.  That isn't happening so I've read many many
> posts, papers, documentation on the cups site and nothing really works
> and much of it references settings in cupsd.conf that get flagged as
> errors  in 1.6.3 or 2.1.3.  Some of the things I've found out.
> 
> * cups-browsed is deprecated so that's not an option
> * Some documentation says add BrowsePoll to the client cupsd.conf but
> the logs on my systems show that as an unknown command and in the 1.6.3
> and 2.1.3 docs it does not exist anymore so I can only assume that
> advice is outdated
> * Avahi is mentioned as a necessity.  It's installed on both my systems
> and running and started before cups. 
> ** Is Avahi really needed to broadcast printers and discover printers
> in cups 1.6.3 and 2.1.3?  There is much confusing advice.  Some docs
> say you must have it, others you don't need it.  Some people say they
> turn it off on their servers and some leave it on so does cups need it
> or not.
> ** If I need Avahi how do I set it up for cups? The /etc/avahi
> directory has only default config files with no services.
> 
> There are two ways I can get the printer to be seen on the client.
> 
> 1.  On the client run the printer setup app and add a printer that is
> ipp://serverfqdn/printername and it then becomes a local printer which
> defeats the purpose of a print server if I have to add printers
> manually to each client.  This actually prints but I have no printer
> options to adjust and the text is super large.
> 2.  I can add ServerName serverfqdn:631 to /etc/cups/client.conf on the
> client but according to cups docs that is not recommended because you
> are allowed only one server and if it goes down there is no printing
> and that's not acceptable to me.  The big problem with this is that if
> I try and print from an application the printer from the server shows
> up but the print button is grayed out.  I've tried this on several apps
> and all have a grayed out print button so this does not work. I've
> tried printing as root also and same thing.
> 
> The lpr -P printername file will print but that's bypassing cups I
> assume?
> 
> So how do I set cups up to have a server that serves up printers and
> clients that simply discover the printers and let the users print to
> them.  Anything that would help clear up the confusion would be
> appreciated.
> ##SELECTION_END##
> Thank you.
> 
> 


Look into your system’s package repository for 
cups-browsed
This daemon is – officially – part of the cups-filters project maintained by 
openprinting.org <http://openprinting.org/> (since cups-1.5), but many Linux distributions configure
their repositories so that cups-browsed is supplied as a separate package.
If not already done, install and configure this daemon. 

As I myself currently don’t use it, I cannot advice if you need it to install
on your clients only or on the server as well (depends on the cups versions
and their interactions with dnssd (bonjour or avahi).

Helge