Comment 50 for bug 973270

gilles, you cannot add more than one attachment to one comment, at least not with the web interface of the Launchpad. Perhaps it works with the e-mail interface (mail with more than one attachment?) or via the API (custom-made application which access Launchpad).

It is really strange that system-config-printer does not show any print queue for you as you have your print queues visible in your application's print dialogs.

Can you post the output of the command

lpstat -v

Can you also check whether you have one or more of these files:

/etc/cups/client.conf
~/.cups/client.conf

If so, attach these files. After that, move the files to another directory (for example your home directory) or rename them. Then run system-config-printer again. Do you see a print queue now? If not, choose "Server"/"Connect ..." in the main menu of system-config-printer. If the "CUPS server:" field contains a remote server, try to replace it by "/var/run/cups/cups.sock" or "localhost". Try also to turn off "Require encryption". Click "Connect" and check whether system-config-printer shows print queues and your applications show the same queues (or you get no queues in both cases). Then try to add a print queue again.

Next possible problem is that your computer perhaps does not reach the printer. Are there perhaps firewalls in your network on the way to the printer? On your computer (UFW?)? On a router between the subnet with your computer and the subnet with the printer? CUPS needs port 631, IPP also needs port 631, JetDirect/AppSocket usually needs port 9100, LPD needs port 515.

Is your printer correctly configured? The protocol which you want to use (JetDirect/AppSocket, IPP, LPD, ...) must be activated in the printer. Check the web configuration interface of your printer (needs port 80). If you cannot reach it, there is something wrong with your network. Note that the configuration of the printer can get lost if you update the printer's firmware or if you use certain reset functions in the printer's web interface.

Can it be that the IP address of the printer has changed? This can especially happen if the printer gets its IP from the router via DHCP. Check the IP in the web interface of the router.

Can you run the command (install the nmap package if needed)

nmap <IP of the printer>

and post the output here?