Quote Originally Posted by AlexDudko View Post
This is default for Ubuntu (and maybe other sudo based distro's) and usually there's no need to change anything. It works good and allows logins with the admin user name and its password.
The admin user is the user which was created within the system installation procedure.
But if root user is set then to log in you must enter root as login name and root password. (This is usually default for su based distro's).
I believe you are correct. All the files in /etc/cups/ are owned by root. The only way that a user on a sudo based distro can can modify a file is to be a system admin (a member of the sudo group in the latest version of Ubuntu).