Installing CSF (Config Server Firewall)
Download the latest version of CSF
# wget http://www.configserver.com/free/csf.tgz
Decompress the downloaded file
# tar -xzf csf.tgz
Navigate to new folder
# cd csf
Run installer
# sh install.sh
Checking for the required modules
# perl /etc/csf/csftest.pl
Enabling CSF
# csf -e
Disabling CSF
# csf -x