In Raring, everytime I connect to the network, Cups installs all the printers in the network automatically, some more than once.
Furthermore, I connect a USB printer to the laptop every now and then. Even though the printer is configured already, another printer is added to the list.
I wish to disable this feature and allow only manual installation of printers. How do I go about it?
I just discovered a, possibly optimal, solution to this mess. There is as service called "cups-browsed" which apparently is responsible for going out on the network and finding all the printers it can locate and install them for you (gee - thanks --NOT). Since this is an Upstart/Systemd job, you can stop the service with:
sudo systemctl stop cups-browsed
Followed by:
sudo systemctl disable cups-browsed
You may still start/stop the service manually if you wish with:
sudo systemctl start cups-browsed
sudo systemctl stop cups-browsed
sudo service cups-browsed stop
Even better, you can prevent the service from ever starting again by adding a simple text file to /etc/init that contains the single word manual. The file must be named
cups-browsed.override
So, just start up gedit with
gksudo gedit /etc/init/cups-browsed.override
put manual in the first and only line and save the file.
On the next Reboot, the service will not be re-started. However, you need not reboot if you've already stopped the service. Once you've placed this file in /etc/init, the service can only be started manually (if and when you need/want it) using:
sudo service cups-browsed start
-or-
sudo service cups-browsed stop`
I have tested this over one reboot. Printing still works fine and so far I am not getting several hundred printers installed anymore after the reboot. Just the ones I installed manually show up.
In /etc/cups/cups-browsed.conf, set directive:
BrowseProtocols none
Afterwards, run service cups-browsed restart and service cups restart. There should be no printers visible, except those you've added yourself.
As mentioned earlier, this is now done in the client-side cups libraries (ie libcups.so, which GNOME and KDE apps link against) and not in the cupsd server. So changing the "Browse" settings in the cups server won't work.
$ ldd /usr/lib/x86_64-linux-gnu/libcups.so.2
...
libavahi-common.so.3 => /usr/lib/x86_64-linux-gnu/libavahi-common.so.3
libavahi-client.so.3 => /usr/lib/x86_64-linux-gnu/libavahi-client.so.3
...
IE this behaviour (of showing remote printers in the Print dialog box) happens even if you turn off your local cups server. You can disable it by turning off the avahi service, but that will disable all zeroconf/mdns related functionality.
However, there is at least a way to turn off most of avahi's functionality (including adding remote printers into the CUPS clients) while keeping the DNS functionality (eg when looking up foo.local-style host names):
edit /etc/avahi/avahi-daemon.conf and in the [server] section, add enable-dbus=no then restart the avahi-daemon service.
I tried all of the above. Modifying Cups did not work in Linux Mint 20, which is based on Ubuntu 20.4. Apparently, Ubuntu and Mint no longer use Cups for Printer discovery, but instead now use Avahi. I think it is a Systemd thing. Setting enable-dbus=no in avahi-daemon.conf somewhat worked, but caused the print menu in LibreOffice to take a long time (maybe 20-30 sec.) to show up, and thus was not a good solution.
The following did work, however, very well:
sudo nano /etc/avahi/avahi-daemon.conf
In that file:
change “use-ip4=yes” to “use-ip4=no”
change “use-ip6=yes” to “use-ip6=no”
Now, only printers that I added manually show up in the "Printers" control panel (Printers-localhost), the HPLIP Toolbox and LibreOffice.
The cups client libraries now also get a list of network printers from Avahi (which implements the protocol known variously as zeroconf or Bonjour or mdns or dns-sd). In older versions of cups, this was only done by the cups server.
You can see what is being broadcast on your network with a shell command like avahi-browse -a | grep Printer
You can disable avahi with sudo service avahi-daemon stop, but that will stop all zeroconf based setup, not just printers.
To disable it simply open terminal Ctrl+Alt+T and type
sudo cupsctl --no-remote-printers
or to edit the
/etc/cups/cupsd.conf
and set
Browsing Off
This solution was found here
Some newer Ubuntus (15.04 and up) may need this command instead:
sudo cupsctl --no-share-printers
It's quite simple to make it stop.
Remove the unwanted printers. Then:
sudo nano /etc/cups/cups-browsed.conf
Change this line: BrowseRemoteProtocols dnssd cups (or whaterver is after it) to none so it reads: BrowseRemoteProtocols none .
Then save the file and reboot.
Solved the problem for me.
Found the solution, if you disable bonjour in HP (probably other printers too) the mystery printer detection is an issue of the past.
The accepted answer by @steve-besch works but is incomplete. As explained below, to me the best approach appears to be patching gtk and and optionally libcups2 in addition to disabling cupsd-browsed.
1. Disable cupsd-browsed as already described
sudo systemctl stop cups-browsed
sudo systemctl disable cups-browsed
You can verify that this works using the printing configuration utility system-config-printer.
2. Patch Gtk such that its print-dialog no longer uses avahi
Create patch print_dialog_without_avahi_discovered_printers.patch:
--- a/modules/printbackends/cups/gtkprintbackendcups.c
+++ b/modules/printbackends/cups/gtkprintbackendcups.c
@@ -4008,7 +4008,7 @@
g_source_set_name_by_id (cups_backend->list_printers_poll, "[gtk+] cups_request_printer_list");
}
avahi_request_printer_list (cups_backend);
// Do NOT add random network printers! avahi_request_printer_list (cups_backend);
}
}
Reinstall gtk with the applied patch:
sudo apt build-dep libgtk-3-dev
apt source libgtk-3-dev
cd $(find gtk* -maxdepth 0 -type d)
git apply --reject --whitespace=fix ../print_dialog_without_avahi_discovered_printers.patch
debuild -b -us -uc --no-pre-clean
cd ..
sudo apt install --reinstall ./libgtk-3-0_*.deb
# do not update (dist-upgrade)
# sudo apt-mark hold libgtk-3-0
Now launch a new Evince PDF Viewer instance and verify that only printers listed in the system-config-printer app show up in the print dialog.
3. Patch libcups2 such that KDE/Libreoffice print dialogs no longer use avahi
Create patch no_discovered_printers.patch:
--- a/cups/dest.c
+++ b/cups/dest.c
@@ -1689,7 +1689,7 @@
data.num_dests = 0;
data.dests = NULL;
- if (!httpAddrLocalhost(httpGetAddress(http)))
- if (1 || !httpAddrLocalhost(httpGetAddress(http)))
{
/*
- When talking to a remote cupsd, just enumerate printers on the remote
Reinstall libcups2 with the applied patch:
sudo apt build-dep libcups2
apt source libcups2
cd $(find cups-* -maxdepth 0 -type d)
git apply --reject --whitespace=fix ../no_discovered_printers.patch
debuild -b -us -uc --no-pre-clean
cd ..
sudo apt install --reinstall ./libcups2_*_amd64.deb
# do not update (dist-upgrade)
# sudo apt-mark hold libcups2
Now launch a new Okular instance and verify that only printers listed in the system-config-printer app show up in the print dialog.
Background
As several answers here point out, printers that were not installed still appear in the print dialog of e.g. the PDF-Viewer Evince or Libreoffice even after having disabled the cups-browsed service. This could be prevented, by stopping the avahi daemon that actually finds these printers in the network: sudo service avahi-daemon stop. However, I strongly advise against this -- for instance it breaks Gnome's scanning app such that it is no longer able to scan and I expect other apps to break as well. Unfortunately, there appears to be no official way to disable only cups filtering in avahi (s. here). Instead, it was suggested to disable this on the level of the printing dialog. S. also here.
Try:
Open http://localhost:631/admin/ → Edit Configuration File or Edit /etc/cups/cupsd.conf
Change:
# Show shared printers on the local network.
Browsing Off
BrowseLocalProtocols none
Reference: cupsd.conf: BrowseLocalProtocols