ssh permitroot login

1. Open up /etc/ssh/sshd_config and set "PermitRootLogin" to "yes". (Your ISP probably set it to "without-password")
2. You also need to restart the sshd process. This is done by killing the existing one (use ps -aux|grep sshd to get the process ID, then use kill to zap it), then restarting /usr/sbin/sshd