Disable Direct Root Login

Inorder to disable direct root login on a linux server, you need to do the following things:

1. vi /etc/ssh/sshd_config in that file make
Permitrootlogin no then save it

2. Restart sshd service

#/etc/init.d/sshd restart

3. Now create a new user and set password for that user.

4. Add that user to the wheel group

# vi /etc/groups

Add that user to the group of wheel by appending the user name to the end of the wheel user entry in 'groups' file

Entry Should look like this:

wheel:*:0:root,user_here

5. Now logon to the server using the username and password and then do
su - and provide the root password to get root access.

Inorder to work this properly you should have the following permission settings

chmod 4755 /bin/su
chmod 1700 /etc/passwd
chmod 1700 /etc/shadow
chmod 1755 /etc/groups

If there is anything wrong with this permission, you may get permission denied or incorrect password errors.

Regards
Nobs