Install csf 

cd /usr/src 

rm -fv csf.tgz 

wget https://download.configserver.com/csf.tgz 

tar -xzf csf.tgz 

cd csf 

sh install.sh  

nano -w /etc/csf/csf.conf

แก้ไข 
TESTING = "0"
RESTRICT_SYSLOG = "3"

csf -r

หาก restart แล้วพบ error ให้ติดตั้ง service เพิ่มเติมตาม error

*WARNING* URLGET set to use LWP but perl module is not installed,

yum install perl-libwww-perl net-tools perl-LWP-Protocol-https -y

install service [HOST]

yum -y install bind-utils

install service [UNZIP]

yum -y install unzip

install service [SENDMAIL]

yum -y install sendmail