[SOLVED] Kubuntu won't rediscover printer

[PatLau]

First of all, I wish to thank the entire Kubuntu and Ubuntu staff and communities, you are doing a great work and it is highly appreciated!

This weekend, I decided to switch from Manjaro KDE to Kubuntu, because I believe there is much more stability, support and compatibility from the Ubuntu and Debian background. I always had difficulty to make any printers and scanners work well in Manjaro.

And as I thought, as soon as I booted on my brand new Kubuntu laptop, the wifi printer got discovered and the right drivers were all automatically installed! (You guys made my weekend right there! )

Unfortunately, the printer just disappeared overnight.

The only unusual things I did last night were this: I installed DejaDup and firewalld, both from the Discover GUI. My spidey sense tells me that firewalld is the cause.

After looking at similar problems on different forums, here is what I did in order to solve this:

I tried to reboot after each time I tried something, didn't work.
I tried to open these ports: 139/tcp, 445/tcp, 137/udp, 138/udp. Didn't work.
I tried: sudo systemctl start cups-browsed , didn't work.

Then, I tried to make it work by manually configuring it, just like I used to do on Manjaro KDE.
System Settings - Printers - Add printer - Manual URI ( socket://PrinterIpAdress ).
Then, I tried to choose the right driver, which wasn't in the default Kubuntu epson driver list. I tried to find it in Discover but I couldn't find anything Epson related.

But since everything was working insanely good after the fresh install, I know the drivers are in there, somewhere...

That's when I gave up trying to make it work over network.

I plugged it in via USB. the printer was automatically detected, however the driver was still missing.

I am in need of your help, and I thank you for your time and assistance,

PatLau

Attached is a screenshot of the Info Center.

[claydoh]

Printer model?
How and what is it connected to?
What happens if you ditch the firewalld? If you are behind a router, is this even necessary? Conflicts between the daemon and the router may be an issue.

As it was working before, and when connected to USB, your specific model is probably using one for a range of devices, so the specific model may not show in the driver list.
When the printer is connected via USB, take a look at the printer settings in System Settings, and note the entry for "Kind", which shows what actual printer hardware is detected and being used, and often the driver is called the same thing.
You can also look at CUPS info from the web interface to get info, using this url: http://localhost:631/
If you click on the Printers tab, then on the printer entry there, you should see possibly more specific driver info. In either case, you should be able to use this in the driver search dialog.

[PatLau]

Thank you claydoh for the quick answer!

The printer is an Epson EcoTank model ET-2750 .
It is connected on my home router by WIFI, with my normal password. The router firmware is flashed with OpenWRT.

I use firewalld on my laptop because it is my work computer, which I carry with me everywhere I go and connect to different WIFIs over VPN.

So, as a fix, I managed to find the right drivers from the official Epson website. I then manually reconfigured the printer using socket://PrinterIpAddress and opened the port 9100 in firewalld. I can now print from wifi, without using the USB! Scanning is another story though. But that, will be for another time!

[jlittle]

I use firewalld on my laptop because it is my work computer, which I carry with me everywhere I go and connect to different WIFIs over VPN.

I wonder why you need a firewall if you use a VPN. I suppose the other end of the tunnel might be dubious, perhaps I should consider using a firewall? I'd appreciate any clues, I seem to be lacking.

[GregM]

Firewall?
Firewall?

Another thing I didn't know existed in Kubuntu.
Where is it and how do I monkey with it?

[Don B. Cilly]

Try
ufw --help
That stands for “uncomplicated firewall” BTW, so you can imagine it is quite complicated ;·)

[claydoh]

I wonder why you need a firewall if you use a VPN. I suppose the other end of the tunnel might be dubious, perhaps I should consider using a firewall? I'd appreciate any clues, I seem to be lacking.

A VPN is more than just a way to hide or obfuscate one's location and have an encrypted connection, as it is primarily used to connect to a private network remotely. Say your work's internal network, or even your home network.
If you are connecting to the internet via unknown or random connections, a firewall on the computer is useful to keep the snoopers out of your system, as the VPN has nothing to do with keeping ports closed to intrusion attempts.

Firewall?
Firewall?

Another thing I didn't know existed in Kubuntu.
Where is it and how do I monkey with it?

The kernel itself comes with a firewall - iptables
ufw makes using it a lot easier:
https://help.ubuntu.com/community/UFW
But you probably really want this:
https://help.ubuntu.com/community/Gufw

Again this not really useful for most unless one is using unknown, insecure connections such public wifi.
it is *really* easy to mess up your connections playing with this
A long layover in Atlanta some years back taught me that :0
And that tethering to my phone and using my data virtually eliminated all the pings and probes and things from the public wifi.

[GregM]

I tried starting it but nothing appeared to happen.
Probably just as well.

[PatLau]

Very good explanations and advises Mr. Claydoh!