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Package: cups
Version: 2.2.1-8
Severity: wishlist
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Hash: SHA256
When setting up a printer, I noticed that it showed up twice on the
'Find New Printers' page. It turns out that one of these entires is from
the dnssd backend, and the other is from the snmp backend.
While both options initially resulted in a working printer, the URL from
the snmp backend makes use of the printer's current IP address:
<socket://192.168.0.20>.
This is problematic on an unmanaged network where IP addresses are not
stable. For instance, I just replaced my home network router with a new
one, resulting in all the addresses on my network being renumbered.
In addition, I noticed that the default setting for DHCP lease time on
my new router is only one hour, so it is possible that the printer would
get a new address simply by turning the printer off, adding a new device
to the network and then turning the printer on again, a process of
events that many users are likely to experience.
If the snmp backend was disabled by default, users would not run into
this problem. It is unclear to me whether this backend is very useful in
the modern world of printers that can be discovered by the dnssd
backend. The experts who assign their printers a static address can
always enable the snmp backend themselves (though I don't know why they
would need it to discover the address of the printer that they just
manually assigned).
- -- System Information:
Debian Release: 9.0
APT prefers testing-debug
APT policy: (550, 'testing-debug'), (550, 'testing'), (520, 'unstable-debug'), (520, 'unstable'), (510, 'experimental-debug'), (510, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: arm64
Kernel: Linux 4.9.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages cups depends on:
ii cups-client 2.2.1-8
ii cups-common 2.2.1-8
ii cups-core-drivers 2.2.1-8
ii cups-daemon 2.2.1-8
ii cups-filters 1.11.6-3
ii cups-ppdc 2.2.1-8
ii cups-server-common 2.2.1-8
ii debconf [debconf-2.0] 1.5.60
ii ghostscript 9.20~dfsg-2
ii libavahi-client3 0.6.32-2
ii libavahi-common3 0.6.32-2
ii libc-bin 2.24-9
ii libc6 2.24-9
ii libcups2 2.2.1-8
ii libcupscgi1 2.2.1-8
ii libcupsimage2 2.2.1-8
ii libcupsmime1 2.2.1-8
ii libcupsppdc1 2.2.1-8
ii libgcc1 1:6.3.0-6
ii libstdc++6 6.3.0-6
ii libusb-1.0-0 2:1.0.21-1
ii poppler-utils 0.48.0-2
ii procps 2:3.3.12-3
Versions of packages cups recommends:
ii avahi-daemon 0.6.32-2
ii colord 1.3.3-2
ii cups-filters [ghostscript-cups] 1.11.6-3
pn printer-driver-gutenprint <none>
Versions of packages cups suggests:
pn cups-bsd <none>
pn cups-pdf <none>
pn foomatic-db-compressed-ppds | foomatic-db <none>
pn hplip <none>
pn printer-driver-hpcups <none>
ii smbclient 2:4.5.4+dfsg-1
ii udev 232-18
- -- debconf information:
* cupsys/backend: lpd, socket, usb, dnssd
* cupsys/raw-print: false
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--- Begin Message ---
Thank you for your report, Sam.
On Tue 07 Mar 2017 at 09:45:42 +0000, Sam Morris wrote:
> When setting up a printer, I noticed that it showed up twice on the
> 'Find New Printers' page. It turns out that one of these entires is from
> the dnssd backend, and the other is from the snmp backend.
>
> While both options initially resulted in a working printer, the URL from
> the snmp backend makes use of the printer's current IP address:
> <socket://192.168.0.20>.
>
> This is problematic on an unmanaged network where IP addresses are not
> stable. For instance, I just replaced my home network router with a new
> one, resulting in all the addresses on my network being renumbered.
>
> In addition, I noticed that the default setting for DHCP lease time on
> my new router is only one hour, so it is possible that the printer would
> get a new address simply by turning the printer off, adding a new device
> to the network and then turning the printer on again, a process of
> events that many users are likely to experience.
>
> If the snmp backend was disabled by default, users would not run into
> this problem. It is unclear to me whether this backend is very useful in
> the modern world of printers that can be discovered by the dnssd
> backend. The experts who assign their printers a static address can
> always enable the snmp backend themselves (though I don't know why they
> would need it to discover the address of the printer that they just
> manually assigned).
There are still very many printers which do not do Bonjour broadcasting
and it can be turned off on those that do. Also, OOTB, the default can
be "off". A default of disabling the snmp backend on the client would
make the printer undiscoverable.
'dpkg-reconfigure cups' is available for those clients which want to
adjust the choice of backends used.
Closing. Sorry.
Regards,
Brian.
--- End Message ---