Printing Only Works on Wired

Recently, my printers are “seen” just fine on both wired and wireless connections, but printing only works when wired.

Any ideas about how to best troubleshoot this?

Try printing a test page or a very small print job.
Wireless networks may have difficulties with heavy jobs.

Are you connected with Ethernet and Wi-Fi at the same time?
Did you try testing only one connection at a time?
Check the firewall zone settings for each interface:

sudo firewall-cmd --get-active-zones
sudo firewall-cmd --info-zone=ZONE_NAME

Are you connecting to the printer by hostname or by IP?
Check resolver settings for each interface:

sudo resolvectl --no-pager status

How exactly the printer is connected to your network?
Does it have its own Wi-Fi interface?

Are your wireless and wired networks served by the router?
Are those networks bridged and using the same subnet?
Is there routing involved between the client and the printer?

Are you connecting to a standalone print server or directly to a printer?
Try sending a print job via the wireless and check for errors/logs/status.

Sounds like something has changed?

Thanks for the comprehensive reply…

Regardless of job size, anything printed when on wireless never seems to make it to the printer; additionally, I am not connected to both wireless and wired at the same time.

There is nothing odd about the firewall settings and I haven’t changed them since it was working, same with resolver settings.

The printer is hard-line connected to the router and each printer has its own designation IP address, which is how they’re connected.

Again, I’ve changed no settings, but printing when on the wireless connection always fails.

When on wifi, what happens when you use your browser and go to http://localhost:631?
One should see the cups web interface and the printers tab should show the printer of concern if it is properly configured.

Clicking on the link for that printer should reveal details about the printer, then the maintenance button should allow one to print a test page.

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Yup, everything there is correct on both wifi and wired; printing is successful only when wired, though.

This almost sounds as if your openwrt router is preventing it.

What does the print queue show when using the cups interface? Does it show prints hung there or does the print queue simply appear to send the job to the printer then they disappear as if actually printed?

The 'show all jobs ’ button should reveal that.

It claims the printer is “unreachable.” Interestingly, when I delete the printer and re-add it with absolutely no settings changes, printing will resume to long as I don’t restart my laptop.

Although this is a recent development, which seems to indicate a software and not hardware issue, I’m replacing my three-year old network switch to see if that (somehow) could be the issue.

Unreachable means it cannot get a return to connection requests. That would seem to imply the issue may be somewhere in the wifi network stack since the wired connection is reliable. It thus could be anywhere in the chain between your PC wifi networking and the router wifi networking. Hardware or software.

Wifi (or anything else actually) may fail in unpredictable ways.

One approach to identify the actual source may be to use a tool such as tcpdump to monitor the actual data sent and received both on the PC wifi interface and on the router interfaces to both the pc and the printer. That would allow you to see what the pc is sending via wifi and the responses from the printer, as well as providing a clue about why the printer is “unreachable”. Comparing the data from wired vs wifi would also be some assistance.

Remember that any broken link in the chain between the cups software and the printer itself can cause that. Includes wifi interface on the PC, wifi interface on the router, software on both, etc.

Another approach may be to completely remove (forget) the wifi connection from the pc then after rebooting add back the connection totally new. Compare the results after doing so. It may change.

Thanks for those suggestions and I’ll get working on them… The one I have already attempted is the final one about completing forgetting and re-adding the wifi connection; no fix there.