[gentoo-user] Network printer not being found

[gentoo-user] Network printer not being found

[Peter Humphrey]

Afternoon all,

Before my trials with booting, and eventually rebuilding everything from the 
ground up, my Lexmark C2425 printer was working fine. Now the KDE system 
settings printer applet can't detect it, even though pinging it works.

Then when I point firefox to localhost:631 cups's behaviour has changed. If I 
click Adding Printers and Classes, instead of a dialogue to let me add a 
printer I now get a help page telling me how to do it at the command line.

Even if I do manage to add the printer, cups reports that it isn't responding. 
I take this to mean I'm not using the right protocol. I've tried IPP, IPPS, 
HTTP and HTTPS, following that help page.

Package.use is the same as before, and I've tried with cups-browsed both 
running and not.

What am I missing?

-- 
Regards,
Peter.

Re: [gentoo-user] Network printer not being found

[Michael]

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On Thursday, 29 October 2020 14:16:17 GMT Peter Humphrey wrote:
> Afternoon all,
> 
> Before my trials with booting, and eventually rebuilding everything from the
> ground up, my Lexmark C2425 printer was working fine. Now the KDE system
> settings printer applet can't detect it, even though pinging it works.

Is the IP address of the printer the same?

When you 'nmap -A -T4 -Pn -v <PRINTER_IP>' do you see open ports?  It should 
offer 80, 443, 515, 9100, 631 depending on the protocols it uses.


> Then when I point firefox to localhost:631 cups's behaviour has changed. If
> I click Adding Printers and Classes, instead of a dialogue to let me add a
> printer I now get a help page telling me how to do it at the command line.

Hmm ... something must be amiss in your setup.  When I go to the 
Administration tab and click to add another printer the familiar cupsd GUI 
offers various protocols to choose from.  Have you set USE="X"?

Bear in mind, I don't use any network upnp autoconfiguration service on my LAN 
and therefore my use flags may be different to yours:

$ equery u cups
[ Legend : U - final flag setting for installation]
[        : I - package is installed with flag     ]
[ Colors : set, unset                             ]
 * Found these USE flags for net-print/cups-2.3.3-r1:
 U I
 + + X            : Add support for X11
 - - abi_x86_32   : 32-bit (x86) libraries
 + + acl          : Add support for Access Control Lists
 + + dbus         : Enable dbus support for anything that needs it (gpsd, 
gnomemeeting, etc)
 - - debug        : Enable extra debug codepaths, like asserts and extra 
output. If you want to get meaningful backtraces see https://wiki.gentoo.org/
wiki/Project:Quality_Assurance/Backtraces
 - - kerberos     : Add kerberos support
 - - lprng-compat : Do not install lp... binaries so cups and lprng can 
coexist. 
 + + pam          : Add support for PAM (Pluggable Authentication Modules) - 
DANGEROUS to arbitrarily flip
 + + ssl          : Add support for SSL/TLS connections (Secure Socket Layer / 
Transport Layer Security)
 - - static-libs  : Build static versions of dynamic libraries as well
 - - systemd      : Enable use of systemd-specific libraries and features like 
socket activation or session tracking
 + + threads      : Add threads support for various packages. Usually pthreads
 + + usb          : Add USB support to applications that have optional USB 
support (e.g. cups)
 - - xinetd       : Add support for the xinetd super-server
 - - zeroconf     : Support for DNS Service Discovery (DNS-SD)


> Even if I do manage to add the printer, cups reports that it isn't
> responding. I take this to mean I'm not using the right protocol. I've
> tried IPP, IPPS, HTTP and HTTPS, following that help page.

You haven't locked down the printer itself to limit which IP addresses it will 
allow connections from?

Have a look here in case there is some step you've missed out:

https://wiki.gentoo.org/wiki/Printing


> Package.use is the same as before, and I've tried with cups-browsed both
> running and not.
> 
> What am I missing?

Cups usually captures informative logs and you can set increased verbosity for 
more detail.  What do these logs report?

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Re: [gentoo-user] Network printer not being found

[Peter Humphrey]

[Some snipping]

On Thursday, 29 October 2020 19:25:47 GMT Michael wrote:
> On Thursday, 29 October 2020 14:16:17 GMT Peter Humphrey wrote:
> > Before my trials with booting, and eventually rebuilding everything from
> > the ground up, my Lexmark C2425 printer was working fine. Now the KDE
> > system settings printer applet can't detect it, even though pinging it
> > works.
> Is the IP address of the printer the same?

Yes.

> When you 'nmap -A -T4 -Pn -v <PRINTER_IP>' do you see open ports?  It should
> offer 80, 443, 515, 9100, 631 depending on the protocols it uses.

It offers 21, 80, 443, 515, 631, 4000, 5001, 9100 and 9500.

> > Then when I point firefox to localhost:631 cups's behaviour has changed.
> > If
> > I click Adding Printers and Classes, instead of a dialogue to let me add a
> > printer I now get a help page telling me how to do it at the command line.
> 
> Hmm ... something must be amiss in your setup.  When I go to the
> Administration tab and click to add another printer the familiar cupsd GUI
> offers various protocols to choose from.  Have you set USE="X"?

That's my fault. I didn't read the display properly. Now, seeing straight(er) 
Find New Printers doesn't find any, and Add Printer just gives me the usual 
manual methods of declaring the printer.

Emerge -pv gives me this:
net-print/cups-2.3.3-r1::gentoo  USE="X acl dbus pam ssl threads usb -debug -
kerberos -lprng-compat (-selinux) -static-libs -systemd -xinetd -zeroconf" 
ABI_X86="(64) -32 (-x32)"

> > Even if I do manage to add the printer, cups reports that it isn't
> > responding. I take this to mean I'm not using the right protocol. I've
> > tried IPP, IPPS, HTTP and HTTPS, following that help page.
> 
> You haven't locked down the printer itself to limit which IP addresses it
> will allow connections from?

Not knowingly. I haven't seen anything on the printer to suggest I can do 
that.

> Have a look here in case there is some step you've missed out:
> 
> https://wiki.gentoo.org/wiki/Printing

Yes, I've done that.

> Cups usually captures informative logs and you can set increased verbosity
> for more detail.  What do these logs report?

Ah! I think it's a pam problem: permission denied. I am in the lp group 
though. Do I also need to be in the lpadmin group? I never have been before.

-- 
Regards,
Peter.

Re: [gentoo-user] Network printer not being found

[Michael]

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On Friday, 30 October 2020 11:20:05 GMT Peter Humphrey wrote:
> [Some snipping]
> 
> On Thursday, 29 October 2020 19:25:47 GMT Michael wrote:

> > Have a look here in case there is some step you've missed out:
> > 
> > https://wiki.gentoo.org/wiki/Printing
> 
> Yes, I've done that.
> 
> > Cups usually captures informative logs and you can set increased verbosity
> > for more detail.  What do these logs report?
> 
> Ah! I think it's a pam problem: permission denied. I am in the lp group
> though. Do I also need to be in the lpadmin group? I never have been before.

Have another look at the above document and in particular pay attention to:

https://wiki.gentoo.org/wiki/Printing#Configuration

You need to add your user to the lpadmin group.

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Re: [gentoo-user] Network printer not being found

[Peter Humphrey]

On Friday, 30 October 2020 11:51:32 GMT Michael wrote:

> You need to add your user to the lpadmin group.

All right. I've never had to do so before, but I have now. I've also set 
USE=zeroconf on /net-print/cups and remerged it. Both cupsd and cups-browsed
are in the default run level. I've even tried connecting via USB-2; when I
plug it in I get this in syslog:

Oct 30 15:51:37 peak kernel: usb 3-7: new high-speed USB device number 9 using 
xhci_hcd
Oct 30 15:51:37 peak kernel: usblp 3-7:1.1: usblp0: USB Bidirectional printer 
dev 9 if 1 alt 0 proto 2 vid 0x043D pid 0x0300
Oct 30 15:51:37 peak kernel: usbcore: registered new interface driver usblp

That all looks okay to me, no? But still cups can't see the printer.

I found a way, eventually. I had to declare the printer manually, under Add 
Printer. I chose ipp and gave it the URL ipp://<ip-addr>/ipp/print. It was 
found instantly and I could set the paper size. But when I print an Amazon 
return label with Firefox, I get just the text with a blank, framed box where 
the QR and bar codes should be.

Google-chrome printed it though.

Emerge -pv firefox returned this:
www-client/firefox-82.0.2:0/82::gentoo  USE="clang dbus gmp-autoupdate hwaccel 
openh264 pulseaudio system-av1 system-harfbuzz system-icu system-jpeg system-
libevent system-libvpx system-webp -debug -eme-free -geckodriver -hardened -
jack -lto -pgo -screencast (-selinux) -wayland -wifi" L10N="en-GB ..."

Am I missing something important from that?

-- 
Regards,
Peter.

Re: [gentoo-user] Network printer not being found

[Michael]

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On Friday, 30 October 2020 16:49:31 GMT Peter Humphrey wrote:
> On Friday, 30 October 2020 11:51:32 GMT Michael wrote:
> > You need to add your user to the lpadmin group.
> 
> All right. I've never had to do so before, but I have now. I've also set
> USE=zeroconf on /net-print/cups and remerged it. Both cupsd and cups-browsed
> are in the default run level. I've even tried connecting via USB-2; when I
> plug it in I get this in syslog:
> 
> Oct 30 15:51:37 peak kernel: usb 3-7: new high-speed USB device number 9
> using xhci_hcd
> Oct 30 15:51:37 peak kernel: usblp 3-7:1.1: usblp0: USB Bidirectional
> printer dev 9 if 1 alt 0 proto 2 vid 0x043D pid 0x0300
> Oct 30 15:51:37 peak kernel: usbcore: registered new interface driver usblp
> 
> That all looks okay to me, no? But still cups can't see the printer.

We're confusing means of communication with the printer, or I am.  The in-
kernel USB Printer support is deprecated and most printer software no longer 
support it.

Instead just the USE="usb" flag when compiling cups should allow you to 
communicate with USB ports on printers and the cupsd GUI should show the 
printer when plugged in to a USB port on the PC.  If you have compiled the USB 
Printer support as a module you'll need to blacklist it so it doesn't load.


> I found a way, eventually. I had to declare the printer manually, under Add
> Printer. I chose ipp and gave it the URL ipp://<ip-addr>/ipp/print.

URLs imply a network connection using an ethernet cable, which is what I 
assume you were trying to set up in the first instance.  Avahi/zeroconf/upnp 
will announce the printer on the network and as long as cups is compiled with 
USE="zeroconf" it should show up when you go to Administration > Add Printer.


> It was
> found instantly and I could set the paper size. But when I print an Amazon
> return label with Firefox, I get just the text with a blank, framed box
> where the QR and bar codes should be.
> 
> Google-chrome printed it though.

This is a browser + printing CSS if one is made available by the website.  
Browsers have different default printing settings, including or excluding 
background images, background colours, etc.  Google-chrome happens to work on 
this occasion, but the web developer ought to have done a better job by also 
providing their preferred CSS for print jobs.


> Emerge -pv firefox returned this:
> www-client/firefox-82.0.2:0/82::gentoo  USE="clang dbus gmp-autoupdate
> hwaccel openh264 pulseaudio system-av1 system-harfbuzz system-icu
> system-jpeg system- libevent system-libvpx system-webp -debug -eme-free
> -geckodriver -hardened - jack -lto -pgo -screencast (-selinux) -wayland
> -wifi" L10N="en-GB ..."
> 
> Am I missing something important from that?

Nothing obvious jumps out, but half of these USE flags do not mean much to me.  
:-/

More knowledgeable contributors on FF compile options should be able to chime 
in.

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Re: [gentoo-user] Network printer not being found

[Peter Humphrey]

On Friday, 30 October 2020 18:23:38 GMT Michael wrote:
> On Friday, 30 October 2020 16:49:31 GMT Peter Humphrey wrote:
--->8
> We're confusing means of communication with the printer, or I am.  The in-
> kernel USB Printer support is deprecated and most printer software no longer
> support it.

The menuconfig Help page gives no hint of that.
-->8
> > I found a way, eventually. I had to declare the printer manually, under
> > Add Printer. I chose ipp and gave it the URL ipp://<ip-addr>/ipp/print.
> 
> URLs imply a network connection using an ethernet cable, which is what I
> assume you were trying to set up in the first instance.  Avahi/zeroconf/upnp
> will announce the printer on the network and as long as cups is compiled
> with USE="zeroconf" it should show up when you go to Administration > Add
> Printer.

It didn't. That's the problem - well, the first one anyway.

I think I'll recover a kernel config from some months ago and see if that 
helps. More straws being clutched at...

-- 
Regards,
Peter.

Re: [gentoo-user] Network printer not being found

[Michael]

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On Saturday, 31 October 2020 12:30:44 GMT Peter Humphrey wrote:
> On Friday, 30 October 2020 18:23:38 GMT Michael wrote:
> > On Friday, 30 October 2020 16:49:31 GMT Peter Humphrey wrote:
> --->8
> 
> > We're confusing means of communication with the printer, or I am.  The in-
> > kernel USB Printer support is deprecated and most printer software no
> > longer support it.
> 
> The menuconfig Help page gives no hint of that.
> -->8

Fair enough.

I recall there being a news item about it some years ago.  Also, the Gentoo 
wiki page mentions it:

https://wiki.gentoo.org/wiki/Printing#Locally_attached_printer_.28USB.29

However, if your network connection to the printer works, there's probably no 
need to get the USB connection going.

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Re: [gentoo-user] Network printer not being found

[William Kenworthy]

On 29/10/20 10:16 pm, Peter Humphrey wrote:
> Afternoon all,
>
> Before my trials with booting, and eventually rebuilding everything from the 
> ground up, my Lexmark C2425 printer was working fine. Now the KDE system 
> settings printer applet can't detect it, even though pinging it works.
>
> Then when I point firefox to localhost:631 cups's behaviour has changed. If I 
> click Adding Printers and Classes, instead of a dialogue to let me add a 
> printer I now get a help page telling me how to do it at the command line.
>
> Even if I do manage to add the printer, cups reports that it isn't responding. 
> I take this to mean I'm not using the right protocol. I've tried IPP, IPPS, 
> HTTP and HTTPS, following that help page.
>
> Package.use is the same as before, and I've tried with cups-browsed both 
> running and not.
>
> What am I missing?
>
Sounds like to clicked on the (somewhat fuzzily named) "adding Printers
and Classes" on the main page - thats actually the help page which you
described.

Try clicking on Administration on the top line and then add printer.

BillK