You may have faced the issue when user root is not able to login in Red Hat and CentOS. Mostly the first thing which come into our mind is might be possible we forgot the password of root and we are not able to login. But apart of this there are other possibilities also which results the failure of root login.

Sharing some of the troubleshooting steps to resolve the user root not login issue.

Forgotten root password

This is mostly happen when we forgot the root password.For resetting the new password we have to boot the Server in Runlevel 1 .

For this “how to” we have already posted in our blog that is Reset Root password in run level 1

Check the no login shell in /etc/passwd file

[root@server ~]# grep root /etc/passwd
root:x:0:0:root:/root:/sbin/nolgin

If you find the above /sbin/nologin in /etc/passwd file for root .Change its login shell into /bin/bash

usermod -s /bin/bash root

for eg.

[root@server ~]# usermod -s /bin/bash root
[root@server ~]# grep root /etc/passwd
root:x:0:0:root:/root:/bin/bash

Check the root account expiration date

chage -l root  (it will show the account information,check the account expiration date).

In case of root account get expired than change it. For troubleshooting purpose we are giving as Never Expired. For more info read man page “man chage “

chage -E never root

[root@server ~]# chage -l root
Last password change                                    : Sep 17, 2011
Password expires                                        : never
Password inactive                                       : never
Account expires                                         : never
Minimum number of days between password change          : 0
Maximum number of days between password change          : 99999
Number of days of warning before password expires       : 7
[root@server ~]#

Check “nologin” directory in /etc

Check nologin directory in /etc . If you find then remove it with help of rm command

ls -ld /etc/nologin && rm -fr /etc/nologin

Check the permission of /etc/securetty

If the permission of file /etc/securetty is other than 644 than it is also one of the problem.
Change /etc/securetty file permission to 644

chmod 644 /etc/securetty

Check the /etc/securetty file’s content

The securetty file must have below given contents and in alphabetical manner. If you find any incorrect information regarding terminals from which root can log in please do remove.

Given below is sample.It may vary as per RHEL/CentOS OS versions.

[root@server~]# cat /etc/securetty
console
vc/1
vc/2
vc/3
vc/4
vc/5
vc/6
vc/7
vc/8
vc/9
vc/10
vc/11
tty1
tty2
tty3
tty4
tty5
tty6
tty7
tty8
tty9
tty10
tty11
[root@server ~]#

Disabled root login in ssh

In case you are trying with ssh to remote host , might be possible in ssh configuration file login to root is not permitted

[root@server ~]# grep Root /etc/ssh/sshd_config
PermitRootLogin no
[root@server ~]#

Then change the value PermitRootLogin yes in /etc/ssh/sshd_config file. And reload or restart the sshd service.

/etc/init.d/sshd reload
 OR 
/etc/init.d/sshd restart