Hi:

Not sure this is the right place to ask, but here goes:

I have a machine running Linux Mint Cinnamon to which I attached a Hewlett-Packard OfficeJet 6700 via USB (I had to attach it locally because its WiFi seems to have bitten the dust). I shared this printer, and set up two other machines that used to access this printer from WiFi to use the "new" shared version printer within minutes (one is Manjaro w/Cinnamon and the other is a laptop with Mint and Cinnamon).

I have as yet been unable to set up the fourth machine on which I have an up-to-date Manjaro with KDE Plasma 5.22.5. Any GUI option for printer discovery or setup that seems like an appropriate thing to click is greyed out. So, I ran hp-setup from the command line and it suggested that I might need to open up ports permitting Plasma to search for printers on either mdns and/or slp. Makes sense, but this is a home network and I never deliberately set up any firewall on this machine so I looked around for the firewall settings.

I should mention that I have another HP printer with a still-functioning WiFi that is still accessible to all of these machines using only WiFi, so some possible issues seem to have been eliminated. I'm assuming that also means any permission and group-assignment issues, but ?? ...

I'm not at all familiar with Plasma, so I may have missed something, but I've scrolled through all the entries in System Settings and found no firewall settings at all. I presume I'm missing something basic, and perhaps port exposure isn't the issue at all, but it seems like as good a place as any to begin.

Thanks for any pointers, and stay safe.