Remove unwanted printers

Question

When I go to printers on localhost or cups, I only see two printers that I want to use...

When I go to settings printers or print dialog from like Libre Office I see bunch of network printers that I don't want to use...

Deleting them from Settings-Printers, does nothing, they show up again...

Ubuntu 20.04

Answer given here, does not help https://askubuntu.com/a/497769/513874

Also cups browsed is disabled

#systemctl status cups-browsed
● cups-browsed.service - Make remote CUPS printers available locally
     Loaded: loaded (/lib/systemd/system/cups-browsed.service; disabled; vendor preset: enabled)
     Active: inactive (dead)

@24601 it does not work, cups-browsed is already disabled I will update my question. — Aleksandar Pavić, Dec 23 '22 at 14:48
Some users want nothing whatsoever to do with cups-browsed. Why leave it on the system? apt purge cups-browsed and report back. — brian_p, Dec 23 '22 at 20:35
@brian_p tried, printers are still here. I think it's something about gnome calling avahi all the time. — Aleksandar Pavić, Dec 26 '22 at 09:55
@AleksandarPavić it is, avahi will add every printer it sees every time. There are q's on au on how to disable avahi ;-) — Rinzwind, Dec 26 '22 at 10:59
https://askubuntu.com/questions/1314634/how-do-i-disable-automatic-printer-discovery-in-ubuntu-20-10 or https://askubuntu.com/questions/205937/how-can-i-disable-avahi-daemon or https://askubuntu.com/questions/761292/how-to-disable-avahi-daemon-in-ubuntu-16-04-lts or https://askubuntu.com/questions/345132/should-i-disable-avahi-daemon — Rinzwind, Dec 26 '22 at 11:00

score 1 · Answer 1 · answered Dec 26 '22 at 15:01

CUPS detects every printer on the network using avahi-daemon. List what it sees with lpstat -l -e.
Entrues marked permanent are print queues set up either manually or automatically with cups-browsed. Localhost displays only permanent entries.
The remaining entries are not print queues. They are simply printers enumerated by CUPS from what avahi-daemon tells it.
Some apps on 20.04 (more on 21.04) can communicate with CUPS to enumerate the non-permanent printers. LibreOffice is one such app.
Only when an enumerated entry is printed to is a print queue formed. The queue lasts for a minute and then disappears. It is a temporary queue.
Therefore, lpstat -l -e shows potential (temporary) and permanent queue entries.
Temporary queues are an important feature of the present and future driverless printing framework.
Disabling or purging avahi-daemon removes the driverless printing benefits and all queues have to be permanent and set up with vendor drivers. Users doing this will run into big trouble in upcoming Ubuntus.
There isn't any way as yet for apps or CUPS to filter enumerated printers.

Thanks @brian_p so it seems like Ubuntu needs new feature to filter those entries (mark some not to be shown). Or something like that... In my case I see like 25 printers... — Aleksandar Pavić, Dec 27 '22 at 07:06

score 0 · Answer 2 · answered Dec 27 '22 at 07:34

So the only way that I was able to disable unwanted printers is to block them via firewall.

Following steps are required:

List all printers via lpstat -l -e
Find their IP's via avahi-browse --all -t -r
Enable and install ufw
Disable individual printers by ufw deny to printer_ip

Remove unwanted printers

2 Answers2