I've been trying to wrap my head around printing today, and I have come
to understand that IPP is the up-and-coming standard for printing
(replacing the older LPD / AppSocket / HP Jet Direct / etc), and more
specifically, that IPPEverywhere is the new and up-and-coming standard
(of which Apple's AirPrint is a variant/extension, more
broadly-supported simply by being older, although not fully documented
as is the newer IPPEverywhere).
It is further my understanding that IPP is supposed to query the printer
for its capabilities (double-sided printing? stapling? A4 paper size in
the tray, etc).
It is further my understanding that IPP can (does?) query the printer
for this info just prior to each print job.
But I also thought that IPP would query the printer for this info when
the printer is added to the client PC. I find that to not be the case,
however, on my Debian Bullseye/sid box, and on a Mac Catalina MacBook.
Am I incorrect about this setup-time polling?
What I mean more specifically is, when I go into the CUPS web interface
to set up a new printer, and go through the Add Printer stuff, and
select "Other Network Printers" / "Internet Printing Protocol (ipps)"
(because the printer is on a different subnet/virtual LAN and therefore
doesn't get autodetected via Bonjour/mDNS/DNS-SD), and then on the next
screen enter the IP address of the printer, I would have expected the
IPP protocol to then handle the rest of the printer setup, but instead
I'm still asked for the printer name and printer model (although I just
now noticed that what is currently selected (I'm not sure it was when I
started this email) is "{current_make_and_model} - IPP Everywhere" -
perhaps this option is doing what I was expecting?).
(If I select that IPP Everywhere option, the next screen errors out
saying "Unable to open PPD file: Missing asterisk in column 1", so I
suspect that option is not doing what I was expecting.)
Any info to help me understand better the process would be appreciated.
Thanks!
--
Kent
- Semi-OT: IPP doesn't auto-configure CUPS? Kent West
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