Useful tricks

Useful tricks

How to find out whether my printer is capable of driverless printing?

  • look for AirPrint among device specification

  • Officially certified printers for IPP Everywhere

  • check manual for enabling CUPS temporary queues - if your printer is seen in the end in CUPS commands that way, your printer is capable of driverless printing

  • [USB devices only] check for IPP over USB (manual here).

How to find out my multifunction device or standalone scanner is capable of driverless scanning?

  • check the device specification and look for eSCL/AirScan/WSD - if any of these are mentioned, the device is capable of driverless scanning

  • most devices which advertise they can do AirPrint are capable of AirScan too

  • [USB devices only] check for IPP over USB (manual here).

How to find out if my USB device supports IPP over USB

Check whether your USB device has a following text in lsusb -v output:

...
      bInterfaceClass         7 Printer
      bInterfaceSubClass      1 Printer
      bInterfaceProtocol      4
      iInterface              0
...

If the device has the bInterfaceClass 7, bInterfaceSubClass 1 and bInterfaceProtocol 4 in the sequence, it supports IPP over USB which is critical for USB device driverless printing and scanning.

How to install a print queue

The answer is you don’t have to install at all :) if your device is new enough, is in your local network or is an USB device, has IPP/AirPrint/mDNS enabled and your avahi-daemon is running, CUPS is able to create a temporary queue for you right away in the print dialog, print via it and remove it after successful printing. But there are still use cases when permanent installation is needed like sharing a print queue, different print queue defaults or printer being in different subnet, so I will cover a permanent instalation too.

How to setup CUPS temporary queues with network printer

If your printer is capable of AirPrint, IPP and MDNS is enabled in your printer and printer is in your local network, then to get CUPS temporary queues working you need:

  • have avahi-daemon running:

$ sudo systemctl start avahi-daemon
  • have cups.socket enabled and running running:

$ sudo systemctl enable cups.socket
$ sudo systemctl start cups.socket
  • enable MDNS in your firewall settings

After this the temporary queue will appear in the print dialog and you don’t need to install a specific print queue unless you have a reason for it.

You can check if your printer is seen in mDNS messages by (avahi-tools must be installed):

$ avahi-browse -avrt
...
= enp0s25 IPv4 HP LaserJet M1536dnf MFP (42307C)             _ipp._tcp            local
   hostname = [NPI42307C.local]
   address = [192.168.1.10]
   port = [631]
   txt = ["UUID=434e4239-4243-4a42-5859-3c4a9242307c" "Scan=T" "Duplex=T" "Color=F" "note=" "adminurl=http://NPI42307C.local." "priority=10" "product=(HP LaserJet M1536dnf MFP)" "ty=HP LaserJet M1536dnf MFP" "URF=CP99,W8,OB10,PQ3-4-5,DM1,IS1-4,MT1-2-3-5,MT1-2-3-5,RS600" "rp=ipp/printer" "pdl=application/postscript,application/vnd.hp-PCL,application/vnd.hp-PCLXL,application/pdf,image/urf" "qtotal=1" "txtvers=1"]
...

and if CUPS or its backends see the printer by commands:

(lists all existing print queues - permanent or temporary)

$ lpstat -e
HP_LaserJet_M1536dnf_MFP_42307C_

or

(lists all devices, which CUPS sees in the local network or USB)

$ lpinfo -l -v
...
Device: uri = ipp://HP%20LaserJet%20M1536dnf%20MFP%20(42307C)._ipp._tcp.local/
        class = network
        info = HP LaserJet M1536dnf MFP (driverless)
        make-and-model = HP LaserJet M1536dnf MFP
        device-id = MFG:HP;MDL:LaserJet M1536dnf MFP;CMD:PDF,PS,PCL,AppleRaster,URF;
        location =
...

How to setup CUPS temporary queues with USB printer

USB printers have only one additional prerequisite, installing ipp-usb, which will transform IPP over USB devices to network printer on localhost:

$ sudo dnf -y install ipp-usb

Then you can follow the steps in manual for network printers.

How to install a permanent print queue

Prerequisties for permanent driverless printers: enable IPP in your firewall, enable IPP on your printer if possible.

Installation via CUPS web UI
  • start cups.service

$ sudo systemctl start cups
  • go to Administration tab

  • click on Add printer

  • enter your credentials

  • choose the found device or the connection you prefer - for driverless permanent queue choose Internet Printing Protocol (ipp)

  • in case you didn’t choose a found device, enter the device uri at the next page - for driverless printers they usually are:

Network printers:
ipp://<printer_IP_or_printer_hostname>:631/ipp/print

USB printers via ipp-usb:
ipp://localhost:60000/ipp/print

Non-driverless printers via printer application:
ipp://localhost:8000/ipp/print/<printer_name>

Printers pointing to a remote CUPS server:
ipp://<server_ip_or_server_hostname>:631/printers/<remote_print_queue>
  • choose device manufacturer and model (IPP Everywhere for driverless printers)

  • set a different default options if needed and finish

Notes:

Adding a permanent queue for driverless USB printers or non-driverless printers installed in a printer application is usually unnecessary, because they are shared by mDNS on localhost, so any application using CUPS 2.0+ API functions (cupsGetDests(), cupsGetNamedDest(), cupsCopyDestInfo()) should be able to pick them automatically (for network printer it depends whether the device is in the same subnet as your machine). Installling them permanently should be necessary only if an application doesn’t use the recent API or to work around a bug which happens when using them as temporary queues.

If there are more devices via ipp-usb or printer applications, they listen on different ports - devices via ipp-usb start on port 60000, separate printer applications start on port 8000.

Installation via CLI commands
  • you will need a device uri - <device_uri>, which you can find by lpinfo -v:

$ lpinfo -v
direct usb://HP/Officejet%20Pro%208500%20A909a?serial=NNNNNNNNN&interface=1
       ====================================================================
network dnssd://Officejet%20Pro%208500%20A909a%20%5B43FD8E%5D._pdl-datastream._tcp.local/
        =================================================================================

or construct it manually - f.e. for IPP printers:

ipp://<IP/hostname>:631/ipp/print

and a driver name - <driver>, f.e.:

$ lpinfo -m
....
everywhere IPP Everywhere
==========
...
$ lpadmin -p <name> -v <device_uri> -m <driver> -E

where <device_uri> and <driver> are underscored strings from previous commands and <name> is a print queue name, which is chosen by you.

How to install a scanner

Scanners in Linux don’t have to be installed the same way as printers are if they are in the same network or connected via USB - you just need sane-backends to be installed and any scanning application will communicate with scanner/multifunction device via the backend which supports the scanner.

However, the older HP scanners and multifunction devices require an additional package - hplip - and its binary plugins downloaded via hp-plugin -i if they aren’t supported by sane-backends already.

How to make driverless scanning work

For LAN located and USB devices:

  • have avahi-daemon enabled and running

$ sudo systemctl enable avahi-daemon
$ sudo systemctl start avahi-daemon
  • enable MDNS in firewall

  • [USB devices only] install ipp-usb

For network scanners in a different network:

  • set the scanner device uri in /etc/sane.d/airscan.conf - see:

man sane-airscan

How to setup mDNS with systemd-resolved

systemd-resolved is enabled and running by default since F33 and can be setup to work with Avahi on mDNS support which CUPS needs - Avahi does the advertising, registering and sharing devices, and resolved will handle '.local' address resolution. It will work with following steps:

  • put MulticastDNS=resolve into /etc/systemd/resolved.conf

$ sudo systemctl restart systemd-resolved
$ sudo nmcli connection modify <connection_name> connection.mdns yes connection.llmnr yes
$ sudo systemctl restart NetworkManager

How to compress files

Example:

$ tar -czvf cups-information.tar.gz /etc/cups cups.logs troubleshoot.txt lpinfo.log

Restarting cups service

You restart cups service with:

su -c 'systemctl restart cups.service'