> I don' t know hwat caused it, perhaps by shh from another
machine.
> What can I do to get rid of this problem.
>
>
When you say you need root permission to power off. Are you doing this from the command
line, or GUI? Are you using Gnome, KDE, or another desktop?
I am doing this from the GUI. I am using Gnome. When I poweroff from the
command line no authentication is required.