The printer itself is a HP LaserJet 8000 in Raum #1.

It is reachable over the LAN, at drucker.realraum.at. It works using the standard cups driver (cups version 3.16.3) hp-laserjet_8000_series-pcl3.ppd.

You can use directly LPRng to print from your computer, no CUPS needed!

The packages you will need (on Debian Stretch) are:

• printer-driver-hpijs
• ghostscript
• foomatic-filters and foomatic-db
• lprng (obviously!)

sudo checkpc -f # Fix various directory permissions
sudo systemctl enable lprng
sudo systemctl start  lprng

Autostarting the LPRng daemon is relatively safe: by default, it only listens on a UNIX socket and drops to a non-root user.

The printer driver needs a PPD file, that you can create out of the foomatic database as follows:

foomatic-ppdfile -p Lexmark-E120n | sudo tee /etc/lprng/Lexmark-E120n.ppd > /dev/null

LPRng comes with an example /etc/printcap file, that you may or may not use. In any case, here is the configuration you actually need:

.common:
	:sd=/var/spool/lpd/%P
	:sh:mx=0:mc=0
	:force_localhost

realraum:tc=.common:lp=drucker.realraum.at%9100
	:if=/usr/bin/foomatic-rip: 
	:filter_options= --lprng $Z /etc/lprng/Lexmark-E120n.ppd: 

Write gtk-print-backends = “file,lpr” in ~/.gtkrc-2.0.

Unfortunately, AFAIK GTK 3 has no support for LPR.