[1] Here is the configuration Examples for CentOS6 that is compatible with Red Hat Enterprise Linux 6.
Download ISO file ( CentOS-6.2-x86_64-bin-DVD1.iso ) for installation from the following site.
[2] Burn ISO file to DVD with an application on your computer and Make an Installation Disk. After finishing it, proceed to next step for installing CentOS6.
I hope you guys will aware of Installing Centos6 so, I am moving to Initial Configs.
Initial Config
[1] Create an admin user.
[root@dlp ~]# useradd yuva
[root@dlp ~]# passwd yuva
Changing password for user yuva.
New UNIX password: # set password
Retype new UNIX password: # Confirm
passwd: all authentication tokens updated successfully.
[root@dlp ~]# exit # logout
[2]Make a user (it's 'yuva' in this example) be only a user who can switch to root as an administration user.
[root@dlp ~]# vi /etc/group # line 11: add user name
wheel:x:10:root,yuva
[root@dlp ~]#vi /etc/pam.d/su
#%PAM-1.0
auth sufficient pam_rootok.so
auth sufficient pam_rootok.so
# Uncomment the following line to implicitly trust users in the "wheel" group.
#auth sufficient pam_wheel.so trust use_uid
#auth sufficient pam_wheel.so trust use_uid
# Uncomment the following line to require a user to be in the "wheel" group.
# uncomment the following line
# uncomment the following line
auth required pam_wheel.so use_uid
auth include system-auth
account sufficient pam_succeed_if.so uid = 0 use_uid quiet
account include system-auth
password include system-auth
session include system-auth
session optional pam_xauth.so
auth include system-auth
account sufficient pam_succeed_if.so uid = 0 use_uid quiet
account include system-auth
password include system-auth
session include system-auth
session optional pam_xauth.so
Forwarding email for root to administration user
[3] Configure that forwarding emails for root to administration user you set above.
[root@dlp ~]#vi /etc/aliases # Person who should get root's mail
# last line: uncomment and change to a user
root:yuva
[root@dlp ~]# newaliases # Configuration change
Firewall
[1] If some firewalls are running in your LAN and iptables in the server is unnecessary, stop it.
[root@dlp ~]# /etc/rc.d/init.d/iptables stop
iptables: Flushing firewall rules: [ OK ]
iptables: Setting chains to policy ACCEPT: filter [ OK ]
iptables: Unloading iptables modules: [ OK ]
[root@dlp ~]# chkconfig iptables off
[root@dlp ~]# chkconfig ip6tables off
