> I know it's a bad idea to log in as root via telnet but I tried once to
> test s/key, and I found something strange.
>
> If you give the bad password, telnetd behaves as usual :
> Login incorrect
>
> But if you give the good one, it says :
> root login refused on this terminal.
>

won't work unless you browse whole /etc/ttys and add "secure" to every
ttyp.

in fact - nonsense.

log in as user and use su.