I was trying to get a new Canon laser printer LBP-7110CW to work with a CentOS 6 machine. It already has an older Canon multi-function laser MF-4720W which worked fine. Both printers are connected via wireless.

The new printer works fine from a Windows machine. The web-based GUI
can be accessed from the C6 machine without problem either. However, CUPS cannot “discover” the printer when adding a new printer although it could probe it successfully if I provide the IP address. Neither could the Canon provided cnnst application find the printer on its own.

This appeared to be related to iptables since it would discover the printer if I disable iptables. I assume the discovery is done by SNMP
so it is a little odd why iptables have to be disabled for the C6
machine to find the printer which is the “server” so to speak.

Ignoring that, the new printer still cannot print after being added. A
process c3pldrv gets stuck at 100% cpu utilization when a print job is sent. A new c3pldrv process will spawn for each print job and remain for hours if I don’t manually kill it.

Throughout this time, the printer can be accessed via its web management gui from the same machine and there is no problem printing to the older multi-function printer. So network connectivity doesn’t appear to the problem.

It also doesn’t make a difference whether I set CUPS to use raw socket or lpd.

The C6 system was updated to the latest files and the latest UFR-II
drivers from Canon was downloaded and installed.

Anybody has any experience or clue about what might be the problem?