I 'm using PuTTY to remote login with root user to my linux server(Fedora core 2, Open SSH) . I changed password and can't remmber . So, i direct login to my server in single mode(some one in forum has instructed me). I using passwd to change root password (some topic has instructed me how to recover password). Right now, i can direct login to server in root user, but can't remote login.
I can remote login with an old normal user, but can't su like before!
I checked sshd_config, and PermitRootLogin yes already.
What is the problem?
Please please help me!, i need it so bad!(i 'm a newbie in linux) (thanks so much for any advice! )

Sorry because of my poor english!

if i was you, i'd login locally, install sudo, edit the sudoers file (using visudo) and add my normal username.
then login from remote site, using the normal username and using sudo gain root privileges.

though this aint really answering your question, it's what is commonly done... as it is discouraged to login as root from a remote site.

I would definitely set AllowRootLogin No -- allowing root logins trough SSH means allowing anybody do brute force attacks against root account, for a start. Generally just *not* a good idea. Instead log in as a regular user and use either su or sudo depending on which one you have or prefer. Definitely, if you can, sudo instead of su (means configuring /etc/sudoers and possibly group 'sudo').

Another matter is why 'su' doesn't work. It really really should. How about if you run 'su' as root to become some other user?
does that work, or not? What error you get if you do that on an account where it "doesn't work"? Better get that fixed first..

Have you made sure the line is not commented? It means you need to remove the "#" before the line because otherwise it is not read. You also need to restart the server for the changes to take effect (IIRC):
But I don't know why you can't su from your user. Perhaps if you explained exactly what you did (which password you changed and so on) then we might be able to help you.

[EDIT]But as has been said, permitting root login can be dangerous if you have a weak password on the root account[EDIT]

Thanks so so so much for all your quick replies!
bakfupai said:"It means you need to remove the "#" "----> yes, it was already removed and i restarted server too!

b0uncer said:"Another matter is why 'su' doesn't work. It really really should. How about if you run 'su' as root to become some other user?
does that work"----->Yes that worked if i direct login to server.


Nathanael: Yeah, i tried sudo too, but it don't work




When i direct login to server I can use su root or whaterver user!

But when i remote login by a user, i can't su root , it displays :"su: incorrect password" but i can use that password to direct login to server in root user.

I have just create a new user.
And i can't remote login with that user too!

I'll just offer a small clarification to what Nathanael wrote. Rather than adding your name in the sudoers fle (with visudo), make your self a member of the "wheel" group and uncomment the line in the sudoers file to allow yourself to use sudo.

i forgot to explain what i did when i recover my root passwd:
Here is what i did:

I restart, in grub menu i press 'e', chose kernel, and press 'e' again , after that i insert an space and the number one '1' then press ENTER and 'b' and ENTER again.
Now i 'm in single mode
i type: passwd
and change root passwd
then restart

I had followed instruction from : http://www.go2linux.org/node/5