Why same CUPS client to CUPS server have different AuthInfoRequired values in printers.conf file

[mdlueck]

I successfully set up Linux CUPS client connections to Linux CUPS server connections last when Xubuntu 20.04 was current. Now Xubuntu 24.04 is current. (So my Linux workstation has undergone now two LTS upgrades... 20.04 --> 22.04 --> 24.04

Then the CUPS client connections to shared printers ended up with:

AuthInfoRequired none

in the printers.conf file. Now on Xubuntu 24.04 building the same connections ends up with:

AuthInfoRequired username,password

in the local printers.conf file! Test print jobs never make it out of CUPS on the workstation.... the jobs are stalled requiring authentication.

Frustrated, I thought to set up a shared CUPS-PDF print share to parallel debug what was going on. I added that to the Linux server, marked it shared in the CUPS configuration. Then connected to it from my same Xubuntu 24.04 system... and that remote printer shows up with:

AuthInfoRequired none

in the local printers.conf file! Test print jobs successfully make it all the way through to the ~/PDF directory of my home directory on the Linux CUPS server. THAT is not even funny! Same CUPS server to same CUPS client, and just magically different printers end up with different AuthInfoRequired values in the client printers.conf file?! What is going on?

Today online I saw one suggestion to vaguely make changes to the workstation cupsd.conf file to adjust authentication. Nothing in the cupsd.conf file calls out per printer properties. So that does not explain why from the same client to the same server, different printers end up with a different value for AuthInfoRequired in the workstation's printers.conf file.

I do not see a way to define the AuthInfoRequired value through the GUI when adding a network printer. According to the comment header in the printers.conf file, the file is auto-generated. But from where does it get generated? Where is the source that insists on putting different values for the AuthInfoRequired property?

The goal is to have:

AuthInfoRequired none

result in the printers.conf file so that print jobs from any source application (Native Linux GUI, terminal programs, Wine programs, VirtualBox VM sessions... all sources of print jobs) running on the workstation may spool over and through to CUPS server shared printers. It is sufficient permissions that people can authenticate with the Linux login. Our environment does not need an authentication layer also in the printing system.

Please kindly advise.

I am thankful.
Michael Lueck