By default root cannot login in gdm ( Gnome display manager ) . The same is true with kdm.
I know how to change that so root can login.
Allowing root to login with gdm is a "security" option.
Why is it unsecure to log in as root in gdm ?
Just curious.
tia for any information.

Logging in as root is a bad idea (tm) because it increases the risk of problems with the computer due to accidental deletion, buggy software, and all those sort of things. And yes, on the off chance you get one of the about a half-dozen linux viruses, it could wreck the whole system.

If you need to do system administration, use su. Or sudo. Or gksu. Or some similar task. No reason to check your email as root.

Oh my God! Never do X as root. This is why most distros that allow this will show a big, annoying, red background when you are logged in as root in X. Ubuntu will not even let you login as root ever! That is good security, IMO. IIRC Windows will force you to make at least ONE other administrating account besides the "Administrator", that is bad security.

Did they frighten you? Do not mind these guys, they are not bad, they just want you to avoid troubles.
If anyway you want to login as root in X
Call the console
#su
[type root pass]
#gdmsetup
Configure gdm and allow it to login as root

Again, these guys are right, Not recommended

By using a root account for your desktop, you reduce the security of your linux box to the level of Windows 95. The root account is allowed to do virtually everything with the system. It has no limitations.

If a program (like your webbrowser) gets hit by a 'virus' or 'exploit', that virus has the same power you have: to do everything. The reverse is also true off course. A normal user account severely limits the abilities of a virus.

Almost all Windows XP boxen runs as Administrator by default. So the Windows 95 is not correct, just "Windows" would do.

And it's not quite that bad... but the point is taken. Of course, the most important thing on a computer is your data, which is still vulnerable even as a user.

In my experience, the main problem with running a graphical environment as root isn't security from viruses, but security from your own software.

Complex graphical software does more stuff "behind the scenes" than you can wrap your mind around. Stuff like GNOME, KDE, Konqueror, Nautilus, or Firefox access oodles of configuration files and settings, and it's really easy to accidentally mess something up which breaks the software for ALL users (not just root). Part of the reason is that this software is assumed to be run NOT as root, so it isn't tested as root much (if at all).

In contrast, when you login as root on a text console, you tend to run much simpler software with a more obviously limited scope. When you use "cd, cp, and mv" to move and copy files, the shell isn't going to mess with any files that you don't explicitely specify. When you navigate around in Konqueror, there are a bunch of temporary files and thumbnail files and .desktop files and .directory files and such which are accessed automatically.

Quite a valid point, IsaacKuo. One that is often overlooked.

So, summing all that has been said the community recommends you not to enter root mode unless for SOME setups and emergencies.

Thank you immensely! I needed this and used it for a few minutes and then revoked the root user login.
I totally agree with everyone though and this should only be done "carefully" and under certain circumstances.