Block root user for login in Graphical mode for security
 

If u want set more security on your server like fedora and redhat u can use this line for block root account login from graphical login screen


Open the file

#vim /etc/pam.d/gdm

and add this line in it

auth required pam_succeed_if.so user != root quiet


now save and exit and reboot your computer now u can only lgoin with root in text mode.