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slot

Member

Registered: 2008-09-08

Posts: 67

cups does not discover network printer

The new version of cups does not find the network printers
On the admin page clicking on 'find new printers' does not discover the printer.
in the help page:
http://localhost:631/help/network.html
I am told to run this:
CUPS_DEBUG_LEVEL=2 /usr/lib/cups/backend/snmp 2>&1 | tee snmp.log
This fails because it cannot read the configuration file unless as root:

DEBUG: No address specified and no Address line in /etc/cups/snmp.conf...

If I chmod 644 the conf file then it seeks for printers, but still does not find them

whaler

Member

From: Oslo, Norway

Registered: 2008-03-25

Posts: 324

Re: cups does not discover network printer

Necrobumping or not - how do you guys make CUPS detect a network printer?
I have an Oki C5750-5B775 cabled to my router, as is my PC.
The printer has a static address (192.168.2.221).
I can ping the printer. NMAP finds it no problem. CUPS (localhost:631/admin) doesn't see a thing.

I have avahi and ms-mdns installed and have disabled systemd-resolved.service because it is allegedly incompatible with avahi.
Running

avahi-browse --all --ignore-local --resolve --terminate

results in nothing. Trying avahi-discover, I get a message about changing some dbus import settings...

Anyway - what exactly should I do to make CUPS discover my printer?

Last edited by whaler (2019-10-10 14:31:19)

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 77,736

Re: cups does not discover network printer

You should first nmap the printer to see whether it has a mdns implementation.
Since you know the IP, you could just add the printer using (likely) the IPP protocol.
http://localhost:631/help/network.html

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whaler

Member

From: Oslo, Norway

Registered: 2008-03-25

Posts: 324

Re: cups does not discover network printer

@seth

Thank you.
As mentioned, nmap sees the printer:

# nmap C5750-5B775
Starting Nmap 7.80 ( https://nmap.org ) at 2019-10-09 16:49 CEST
Nmap scan report for C5750-5B7775 (192.168.2.221)
Host is up (0.00023s latency).
Not shown: 997 closed ports
PORT     STATE SERVICE
80/tcp   open  http
515/tcp  open  printer
9100/tcp open  jetdirect
MAC Address: (...) OKI Electric Industry)

Looking closer at it now, it seems the printer accepts connections only on the ports reported.
When I set it up to use JetDirect on port 9100, the printer responded.
Now that I can connect, I can also check the printer's internal settings.

Thanks again for the heads up!

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 77,736

Re: cups does not discover network printer

ftr, avahi/mdns/bonjour/ihavenoideawhatthefuckingofficialnameis would run on port 5353, ie. the printer simply doesn't support that.

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