SU Authentication failure

Phil Sexton philsexton at
Sun Jun 15 20:39:13 UTC 2008

John wrote:
> Hi
> Having just upgraded to Hardy Heron 8.04, I've been trying to use a 
> terminal window to su to change a configuration in /etc/bluetooth.
> I keep getting an Authentication failure which I don't remember from 
> Version 7.
> If I change a setting in, say, the network configuration using the  
> System -> Administration -> Network menu option, is asks for 
> authorisation and accepts my password.
> Why does su not let me in?

The root password is locked by default for security reasons, so sudo 
is the recommended way.

You can set a root password, however by:

sudo passwd

To re-lock the root password:

sudo passwd -l root

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