Initial Server Setup with CentOS

adduser i88
passwd

visudo

i88    ALL=(ALL:ALL) ALL

sudo vi /etc/ssh/sshd_config


PermitRootLogin no
UseDNS no
AllowUsers i88

/etc/init.d/sshd reload

Test you can login with the new user i88 before logout.

You may then go ahead with 

Installing RHEL EPEL Repo on Centos