Solution for failure of Su authentication when Ubuntu obtains Root User Permissions

Ubuntu
After installation, the root user is locked by default and cannot log on or "Su"
Root. Some people say this is a bad practice, especially for servers. I think it should be more secure for desktop users, but it can be set to "allow Su" for servers.
To root, but root users are not allowed to log on directly ". For the convenience of development, I use this method on both the desktop and server.

◆ Allow Su to root

It is very simple. The following is the setting method:
Me @ tipfoo :~ $ Sudo passwd
Password: <--- enter the password of the user during installation
Enter new Unix Password: <--- New Root User Password
Retype new Unix Password: <--- repeat the New Root User Password
Passwd: the password is successfully updated.
◆ Allow root login

If you want to allow root logon (not recommended), perform the following operations:
Me @ tipfoo :~ $ Gksu/usr/sbin/gdmsetup
(Or use the desktop menu: system> System Management> logon window)
Click the "Security" option page and select "Allow Local Administrator Logon ".
Note: This step depends on the previous step.
◆ Directly log on without entering the password

Someone complained on the forum that Ubuntu in the House could not be logged on like window $ -- without a password. In fact, the same can be done:
On the "Security" option page in the previous step, select:
"Enable Automatic Logon" and "user" (for example, "me ");
Note: Do not set this for public computers!
◆ Log on to the remote server through SSH

If the remote server only allows the root user to SSH to the server, you must "Su to root" in Ubuntu to log on successfully (depending on the server configuration ).
First, copy the key to the "/root/. Ssh/" directory,
Me @ tipfoo :~ $ Su
Password:
Root @ tipfoo:/home/me # chmod 600-r/root/. Ssh/
Root @ tipfoo:/home/me # ssh-P 27482 11.22.33.44
Enter passphrase for key'/root/. Ssh/id_rsa ':
Last login: Thu Jun 21 14:29:00 2007 from 11.22.33.45