PRO-300 IP address hardcoded into various files for drivers/apps

[chrispnw]

I'm sharing this experience in the hope it reaches the printer software engineering/design team(s).

I recently replaced my home wifi router, which changed the DHCP-assigned IP address for my PRO-300. When I tried to print via Professional Print & Layout, the Job Manager was still targeting the printer's old IP address. I tried several fixes (updating firmware, updating both the CUPS driver and PP&L software, restarting the printer, and removing/re-adding the printer in macOS's Printers & Scanners), but the app kept trying the old address.

After more than an hour of troubleshooting (with help from Claude AI), it turned out the old IP was hardcoded in at least three separate Canon-managed config files on disk, independent of both the macOS printer queue and each other: one tied to the printer driver's internal device registry, one in PP&L's general printer info file, and one in a saved "Favorite" preset. Fixing only one or two wasn't enough since the app appears to re-propagate the old value from one file to the others on launch, so all three had to be corrected before printing worked again.

Storing the printer's network address independently in multiple places, with no single source of truth and no re-discovery mechanism when a printer's IP changes, is not a great design, and I wouldn't be surprised if this is a problem for others. An automatic or manual "reconnect" or "refresh printer connection" option that re-resolves the address using the printer's serial number or Bonjour name would go a long way. More fundamentally, though, macOS already handles device discovery and connection through its own printer subsystem — there shouldn't be a need for the app to cache and hardcode IP addresses on its own at all.

If this has already been reported, my apologies. I couldn't find a prior thread on the topic and I hope this finds its way to the right team(s).

[SignifDigits]

Unfortunately, this is primarily a group of users and your report isn't assured of making it's way to bug fixes.  I suggest that you reach out to Canon Support and also use the "[+] Feedback" on that page - https://www.usa.canon.com/support 

On Windows some Canon software also leaves residual parameter files in the user file space after uninstall, so I suppose it's not surprising that is also true for Apple.   I assume it's helpful for most users in that the software recalls the last folder where it was operating, but in some cases it is undesirable.

[donaldolsen]

That's handy information. Canon should be using macOS discovery for printers and avoid saving multiple IPs or maybe offer a simple Refresh printer connection "button".

[chrispnw]

Thanks for your reply. I would love to provide feedback, but I see no mechanism to do so. The support page doesn't provide any feedback form as far as I can tell. Perhaps I'm missing something.

I've submitted a form on the Contact Us page, but that will go to a sales rep for commercial printers (the closest match to this issue). Hence my post to this forum in the admittedly tiny hope it will make its way to the product team 🙂 And perhaps it would help someone who has this issue in the future and lands here. 

[SignifDigits]

You have to select a product first.  Go to https://www.usa.canon.com/support/p/imageprograf-pro-300  then click "[+] Feedback".  If you click it the following should open for you to type into.

[shadowsports]

Greetings,

@chrispnw 

I own a couple of Canon Laser Printers so I'm not using the professional print & layout application. Why not reserve the same IP address on your router?  If that is truly what your problem is. Then uninstall and reinstall the printer is an IP printer.

There's likely a workaround for this issue but at least it could be mitigated by using the previous IP address which can be your choosing.  

Further, you missed some crucial steps like resetting the printer subsystem in Mac OS. Then completely removing the applications which might be harboring configuration information.  Of course updating an existing install is going to keep some of the pre-existing information.  You would need to remove everything after the printer subsystem reset, restart the MAC and then re-add the printer as an IP device.  Then reinstall the applications.  Again,  I think it's possible that you didn't go far enough.  You introduced this problem when you changed the IP address.  Don't rely on DHCP, Bonjour or AirPrint as a means for device configuration.  Your router is the single source of truth.  I'd be more than happy to work on this with you further.

[chrispnw]

Aha--I was going crazy trying to find the + and finally found it at the very top of the page, not in the substance of the page itself, which is where I was looking for it or some other feedback/contact method. I've now copy/pasted my post into the feedback form 🙂

Thanks for the pointer!

[chrispnw]

I agree that reserving the previous IP address in the router would have nipped all of this in the bud. It's still bad design to essentially hard code the IP address in multiple files without an apparent source of truth. 

FWIW, the new router defaults to 192.168.4.xx for its addresses and the old router used 192.168.0.xx for its addresses. I suppose there’s a way to reassign the default subnet settings in the router, but it wasn’t an issue for the umpteen other devices connected to my network since they must rely on the router SSID/pwd, which I did set to the previous SSID/pwd. Regardless, the new PRO-300 IP address is reserved in my new router so until I replace this one (and subsequently forget about it lol), I’m good to go.

Aside from deleting and adding the printer multiple times and various methods, including adding the printer by IP address, as well as restarting my Mac and printer multiple times, I'm not sure what I would do differently. Deleting and reinstalling the Canon software did not work, either, since it left behind configuration files that were not removed or overwritten by my deletion/addition of the printer. 

The fundamental issue is that the Canon software itself encodes the IP address in a few different files—independent of the operating system. And it must do so when first executing, never to return for an updated address. So when executing the print operation, it apparently doesn't bother to search for the printer's current IP address. It took some sleuthing to find those files and overwrite the various lines with the new IP address. BTW, I’m sure I could’ve blown away those files when I found them, thus triggering the creation of a new set of files, but I didn’t want to take the chance of losing the settings for paper profiles/etc. that might have been there.

BTW2, I don't understand why it should've been this difficult to chase down. I have a decent amount of technical knowledge, so I had least had a running start when I saw that the printer job monitor showed it was trying to use the wrong IP address, but sheesh. I wonder what non-techies do when they run into these issues.