but neither do I see the NVT under /nvts, nor can it be found by searching for “maximum password age” or going directly to the NVT /nvt/1.3.6.1.4.1.25623.1.0.109104 ?
Most Policy / Compliance VTs (including the mentioned with the 1.3.6.1.4.1.25623.1.0.109104 OID) are only part of the commercial Greenbone Security Feed (GSF). See the following description and the linked PDF for more info on the differences:
Is it possible to see if the required NVTs are available in any of the commercial GSF? I found https://secinfo.greenbone.net but it seems to be down since Friday, May 8, 2020, at least according to the page’s modification date.
We currently use GCE to learn more about Greenbone/OpenVAS. In the Greenbone OS Administration there is an option to enter a Greenbone Security Feed Key. Say a valid key is entered, do I understand it correctly that any commercial Feed is not supported with GCE’s Webinterface called Greenbone Security Manager (GSM)?
Is it possible to buy only certain NVTs like the ones mentioned in first post?
the Greenbone Community Edition VM (GCE) is derived from our GSM One product. Although it would be technically possible to add a key for our commercial Greenbone Security Feed (GSF) to the GCE you can’t do this (at the moment). It is required to buy a GSM to get a key for the GSF. Greenbone doesn’t sell licenses for the GSF without an appliance (at the moment).