I have a problem using a HP network scanner on Debian Stretch. Exactly the error I have is reported and solved on some forum.

The recommended solution is to set the SNMP community string to public for read and write.

Unfortunately Debian Stretch installs SNMPv3 which has a much more developed security model.

I don't need that, I don't want that. In the snmpd config file the old community strings cannot be configured anymore.

Now every web page about Debian states that SNMPv3 can be used in a number of ways depending on the “securityLevel” configuration parameter. One of them is
Which is exactly what I want. But NONE of those pages actually tell HOW to set the securityLevel to noAuthNoProv

So how do I totally disable security in SNMP?
Or alternatively: how do I emulate SNMPv2 behaviour and have the read and write community set to public?

jlinkels

Follow-up: It seems that the strings to set the community SNMPv2 styles are:
Unfortunately I cannot test if it works. Thing is, I am trying to get a networked scanner to work using libsane-hpaio. The scanner reports "Device busy". It was reported that this error could be worked around by setting the write community to public.

Eventually I set up an SSH tunnel to the scanner and tried to scan through the web interface. To my surprise the scanner really produces a "Device busy" error. No sane or hpaio involved.

Unfortunately this scanner is 9000 km away from where I am and in a different time zone. So I can't ask anyone to power cycle the scanner.

This problem is especially nagging because when I was next to the scanner with my laptop running Debian Jessie, scanning over the network worked perfectly well. Now I try to do this from a headless server running Stretch, no DE install. So the conditions are very different.

Once the scanner is not busy anymore and the same error persists, I continue troubleshooting. I seems complicated, sane-backend, SNMP....

jlinkels

Follow-up:

In the mentioned scanner problem it was not needed to grant write access to the community. As a matter of fact without any modification to SNMP the libsane-hpaio worked well.

The problem was caused by the state of the scanner itself which reported to be busy. The reason is yet unknown. Someone has corrected that but did not report.

It is worth to mention though that libsane-hpaio produced hundreds of SNMP error messages about missings MIBs before SNMP was installed. Installation of libsane-hpaio did not pull in SNMP as dependency. I am not sure whether libsane-hpaio would have worked without SNMP.

For the record, this is what needs to be installed for SNMP and get rid of the MIB error messages.
jlinkels