Red Hat

Hi everyone ...

( Linux Cent OS ) i cant login as root user in my lab machine ... i did give correct root and root passwd ..but it showing Authentication Failed ...

plz help me

Boot the machine in maintenance mode by appending below in the grub entry for the kernel parameters

Code:

init=/bin/sh

Mount the root filesystem as r+w (if /etc is a different filesystem, you need to mount it r+w too)

Code:

mount -o remount,rw /

Run the passwd command and reset root's password

Code:

/usr/bin/passwd

Reboot the machine and check

Code:

reboot

This is just the preliminary troubleshooting step. If this does not work, need to check if other users (except root) are getting the same error message or not, which might tell us if it's a PAM issue. Also, you could look into /var/log/secure file to see what exactly is getting denied.

hi Admin ..

i tried what you said .. no luck ....still saying Authentication Failed
and i also i check /var/log/secure it saying following ..

Code:

pam_unix(login:session):session opened for user root by (uid=0)
Permission Denied
pam_unix(login:auth):authentication failure: logname=LOGIN uid=0 euid=0 tty=tty1 ruser= rhost= user=root

plz how to fix ..step by step..

Moderator's Comments:

Code tags for code, please.

Is SELinux enabled? If so, can you check if any related AVC denials in /var/log/audit/audit.log ?

And on top of all, do you remember anything you did that could break PAM authentication? Does the same happen when trying to log in as a different user?

i newbie on linux ....
SElinux is Disabled ....
i dont disturb any PAM authentication

help me .. how to resolve and login as root and other