Add OS User to the Wheel Group.

Step 01: Add user and set the password

[root@Teletalk ~]# adduser tamim
[root@Teletalk ~]# passwd  tamim
Changing password for user tamim.
New UNIX password:
BAD PASSWORD: it is based on a dictionary word
Retype new UNIX password:

Step 02: Add user Oracle and Tamim user to the wheel Group

visudo is a wheel user group config file User privilege specification

[root@Teletalk ~]# usermod -G wheel oracle
[root@contentserver root]# id oracle
uid=500(oracle) gid=500(oinstall) groups=500(oinstall),10(wheel),501(dba)

[root@Teletalk ~]# usermod -G wheel tamim
[root@Teletalk ~]# id tamim
uid=500(tamim) gid=500(tamim) groups=500(tamim),10(wheel)

Step 03: Uncomment the Wheel group in /etc/pam.d/su

[root@Teletalk ~]# vi /etc/pam.d/su
auth       required     /lib/security/$ISA/pam_wheel.so use_uid

Step 04: Modify the the /etc/ssh/sshd_config file.

Add following Line (AllowUsers  oracle tamim) in the sshd_config file which allow oracle and tamim to login, Also uncomment PermitRootLogin and set PermitRootLogin no rather then yes

[root@Teletalk ~]# vi /etc/ssh/sshd_config
AllowUsers  oracle tamim

PermitRootLogin no

Save the file Ctrl+X then Y then enter

Step 05: Restart the sshd Service

[root@Teletalk ~]# service sshd restart
Stopping sshd:                                             [  OK  ]
Starting sshd:                                             [  OK  ]

Now you can’t login as a root user remotely by using ssh client or putty. You have to login as a oracle or tamim the swatch user to root.