network printer discovery

[Neal Becker]

Network printer discovery is not currently working.  I have used this
printer before from this fedora laptop, but now cups can't communicate with
it, and if I try to add printer, no network  printers are discovered.  I
can get to the printer's web page from this laptop, and I can print from
other devices.

What could I do to troubleshoot this?

Thanks,
Neal

[Ted Roche]

On Mon, Aug 17, 2020 at 11:17 AM Neal Becker  wrote:
> Network printer discovery is not currently working.  I have used this
> printer before from this fedora laptop, but now cups can't communicate with
> it, and if I try to add printer, no network  printers are discovered.  I
> can get to the printer's web page from this laptop, and I can print from
> other devices.

I dropped the local workstation firewall (in my case, with sudo systemctl
stop firewalld) to get discovery to work. After CUPS had the printer
configured, I could re-start the firewall.

[Neal Becker]

If I stop firewall (systemctl stop iptables) I can communicate with the
printer.  If I restart the firewall I get "unable to locate printer".
My printer is
dnssd://Brother%20HL-L2395DW%20series._ipp._tcp.local/?uuid=e3248000-80ce-11db-8000-3c2af4436b47

Any ideas?

On Mon, Aug 17, 2020 at 11:38 AM Ted Roche  wrote:
> On Mon, Aug 17, 2020 at 11:17 AM Neal Becker  wrote:
> > Network printer discovery is not currently working.  I have used this
> > printer before from this fedora laptop, but now cups can't communicate with
> > it, and if I try to add printer, no network  printers are discovered.  I
> > can get to the printer's web page from this laptop, and I can print from
> > other devices.
>
> I dropped the local workstation firewall (in my case, with sudo systemctl
> stop firewalld) to get discovery to work. After CUPS had the printer
> configured, I could re-start the firewall.
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[PGNet Dev]

On 8/23/20 10:52 AM, Neal Becker wrote:
> If I stop firewall (systemctl stop iptables) I can communicate with the printer.  If I restart the firewall I get "unable to locate printer".
> My printer is
> dnssd://Brother%20HL-L2395DW%20series._ipp._tcp.local/?uuid=e3248000-80ce-11db-8000-3c2af4436b47
>
> Any ideas?

if you want _discovery_ to work, open the discovery ports in your firewall for your LAN

https://www.cups.org/doc/firewalls.html

since you appear to be using ipp/tcp, that'd be

631 (IPP/IPPS)

for cups browsing.

do NOT open access to _external_ networks.

generally useful read here:

https://en.opensuse.org/SDB:CUPS_and_SANE_Firewall_settings

if you just want to _access_ your printer at a known/fixed IP, set it up manually

https://www.cups.org/doc/network.html

[Neal Becker]

Thanks!  Good info.  After opening port 5353 udp it seems to be working
fine.
I could have setup manually, but wasn't sure what the URI should be.

On Sun, Aug 23, 2020 at 2:31 PM PGNet Dev  wrote:
> On 8/23/20 10:52 AM, Neal Becker wrote:
> > If I stop firewall (systemctl stop iptables) I can communicate with the
>
> printer.  If I restart the firewall I get "unable to locate printer".
> > My printer is
>
> dnssd://Brother%20HL-L2395DW%20series._ipp._tcp.local/?uuid=e3248000-80ce-11db-8000-3c2af4436b47
> > Any ideas?
>
> if you want _discovery_ to work, open the discovery ports in your firewall
> for your LAN
>     https://www.cups.org/doc/firewalls.html
>
> since you appear to be using ipp/tcp, that'd be
>     631 (IPP/IPPS)
>
> for cups browsing.
>
> do NOT open access to _external_ networks.
>
> generally useful read here:
>     https://en.opensuse.org/SDB:CUPS_and_SANE_Firewall_settings
>
> if you just want to _access_ your printer at a known/fixed IP, set it up
> manually
>     https://www.cups.org/doc/network.html
>
> users mailing list -- [e-mail]
> To unsubscribe send an email to [e-mail]
> Fedora Code of Conduct:
> https://docs.fedoraproject.org/en-US/project/code-of-conduct/
> List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
> List Archives:
> https://lists.fedoraproject.org/archives/list/[e-mail]

[PGNet Dev]

On 8/23/20 12:55 PM, Neal Becker wrote:
> Thanks!  Good info.  After opening port 5353 udp it seems to be working fine.
> I could have setup manually, but wasn't sure what the URI should be.

https://wiki.archlinux.org/index.php/CUPS/Printer-specific_problems

...
    HL-L2395DW 	brother-hll2395dwAUR 	Use the socket protocol as described in #Network printers
    ...

https://wiki.archlinux.org/index.php/CUPS/Printer-specific_problems#Network_...

For network printers, use ipp://printer_ip/ipp/port1 as printer address. For some older printers, this might not work. If not, try lpd://printer_ip/BINARY_P1 instead.

Some printers use the socket protocol. For these printers, use socket://printer_ip:9100. For http, use http://printer_ip/POSTSCRIPT_P1.