On Mon, 8 Sep 2025 23:51:31 -0400
Hendrik Boom <hendrik@???> wrote:

> On Tue, Sep 09, 2025 at 11:03:23AM +1000, Tom via Dng wrote:
> > On 9/9/2025 10:52, Hendrik Boom wrote:
> > > A few months ago I stppped being albe to print on my Brother laser printer.
> > > In today's atteopt I successfuly used qpdfview to show me a pdf file,
> > > and then asked qpdfview to send it to the printer.
> > >
> > > After a while.a message appeared at the bottom right of the laptop screen:
> > >
> > > System Config Printer
> > > Nor connected?
> > > Printer
> > > 'Brother_HL-3170SDW]_
> > > may not be connected.
> > >
> > > This is the message I've been getting for the past few months,
> > > A few months ago, when it worked, instead a light on the printer
> > > would start to flash, indicating it was receiving data.
> > > Eventually printed pages would emerge.
> > >
> > > Presumably there is now difficulty reaching the networked printer.
> > >
> > > The printer itself is able to print test pages when operated from
> > > its own front panel.
> > > It reports its IP number of the LAN as being 192.168.1.4, obtained
> > > by DHCP.
> > >
> > > Other devices on the LAN are accessile from my laptop.
> > > Presumably my laptop is now unaware of the printer's IP number,
> > > Although it worked fine a few months ago.
> > >
> > > But ping on the laptop can reach the printer:
> > >
> > > root@midwinter:~# ping 192.168.1.4
> > > PING 192.168.1.4 (192.168.1.4) 56(84) bytes of data.
> > > 64 bytes from 192.168.1.4: icmp_seq=1 ttl=255 time=32.1 ms
> > > 64 bytes from 192.168.1.4: icmp_seq=2 ttl=255 time=16.3 ms
> > > 64 bytes from 192.168.1.4: icmp_seq=3 ttl=255 time=14.6 ms
> > > 64 bytes from 192.168.1.4: icmp_seq=4 ttl=255 time=16.5 ms
> > > ^C
> > > --- 192.168.1.4 ping statistics ---
> > > 4 packets transmitted, 4 received, 0% packet loss, time 3005ms
> > > rtt min/avg/max/mdev = 14.556/19.871/32.108/7.105 ms
> > > root@midwinter:~#
> > >
> > > So thereis indeed *something* at the IP address the printer
> > > claims belongs to it.
> > >
> > > Presumably something has changed.
> > >
> > > I use CUPS.
> > > CUPS does appear to be installed(so aptitude informs me),
> > > and it all seemed to work a few months ago..
> > >
> > > But now firefox cannot connect at http://localhost:631
> > >
> > > Isn't that the normal way to configure printers on CUPS?
> > > Or has something changed?
> > >
> > > I'm inclined to suspect that somthing has gone wrong
> > > with CUPS. Of cuorse I could be completely wrong and need
> > > to look elsewhere.
> > >
> > > -- hendrik
> >
> > Do you still have the cups-daemon package installed? On my system
> > that is providing /usr/sbin/cupsd and /etc/init.d/cups.
> > /usr/sbin/cupsd is serving port 631 here.
> >
>
> It appears to exist, but is not serving port 631.
>
> root@midwinter:~# lsof -i :631
> root@midwinter:~# which cupsd
> /usr/sbin/cupsd
> root@midwinter:~#
>
>
> It looks as if nothing is listening to :631
> Maybe an init problem? Try to start the service.
>

> root@midwinter:~# /etc/init.d/cups start
> Starting Common Unix Printing System: cupsd.
> root@midwinter:~# lsof -i :631
> root@midwinter:~# ps -Al | grep cups
> 0 S     0  1517     1  0  80   0 -  6510 -      ?        00:00:07 cups-browsed
> 4 S     0  1533     1  0  80   0 -  4142 SyS_ep ?        00:00:02 cupsd

>
> Still no one listening to :631, even though cupsd is running.
>

> > # lsof -i :631
> > COMMAND  PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
> > cupsd   1818 root    5u  IPv6  34498      0t0  TCP localhost:ipp (LISTEN)
> > cupsd   1818 root    6u  IPv4  34499      0t0  TCP localhost:ipp (LISTEN)

> >
> > Check if the cups service is running.
> > Do you have https-only (port
> > 443) enabled for localhost:631?
>
> How would I do that? Or how would I have done that?
>
> -- hendrik
>
> >
> > I connect successfully here to a brother laser printer using AirPrint
> > (bonjour/avahi/zeroconf) from a macos system but I guess IPP from
> > linux should also work. Check the printer on-device setup menu to see
> > if any networking/printing protocols have been disabled?
>
> The printer's networking status print-out says just bou everything
> is enabled, except for
>
> IPv6 Disabled
> Proxy Disabled
> Brother Online Con. Disabled
> IP Filter Disabled
>
> > Nmap can
> > also be useful here to check remote services.
> >
> > Tom

Hi,
here printing and scanning works, installed packages are:

cups-browsed/stable,stable-security,now 1.28.17-3+deb12u1 amd64 [installed,automatic]
cups-bsd/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed]
cups-client/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed]
cups-common/stable,stable-security,now 2.4.2-3+deb12u8 all [installed,automatic]
cups-core-drivers/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed,automatic]
cups-daemon/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed,automatic]
cups-filters-core-drivers/stable,stable-security,now 1.28.17-3+deb12u1 amd64 [installed,automatic]
cups-filters/stable,stable-security,now 1.28.17-3+deb12u1 amd64 [installed,automatic]
cups-ipp-utils/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed,automatic]
cups-pk-helper/stable,now 0.2.6-1+b1 amd64 [installed,automatic]
cups-ppdc/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed,automatic]
cups-server-common/stable,stable-security,now 2.4.2-3+deb12u8 all [installed,automatic]
cups/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed,automatic]
libcups2-dev/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed]
libcups2/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed,automatic]
libcupsfilters-dev/stable,stable-security,now 1.28.17-3+deb12u1 amd64 [installed,automatic]
libcupsfilters1/stable,stable-security,now 1.28.17-3+deb12u1 amd64 [installed,automatic]
libcupsimage2-dev/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed]
libcupsimage2/stable,stable-security,now 2.4.2-3+deb12u8 amd64 [installed]
printer-driver-hpcups/stable,now 3.22.10+dfsg0-2 amd64 [installed,automatic]
python3-cups/stable,now 2.0.1-5+b4 amd64 [installed,automatic]
python3-cupshelpers/stable,now 1.5.18-1 all [installed,automatic]

maybe "apt-get install --reinstall" all of them will fix things?

Cups is reachable at 127.0.0.1:631 via web browser, but setup was done with

system-config-printer

system-config-printer/stable,now 1.5.18-1 all [installed,automatic]

Init scripts are:

ls -la /etc/init.d/cups*
-rwxr-xr-x 1 root root 2804 Aug 21 2019 /etc/init.d/cups
-rwxr-xr-x 1 root root 1961 Apr 10 2019 /etc/init.d/cups-browsed

which are regularly run at boot starting 2 daemons.

Do you use any firewall?
All config files are in /etc/cups:
/etc/cups/printers.conf
has the configs for the printers.

Hope this helps.

Ciao,
Tito