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
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