CSF stands for Configserver security and firewall., is a firewall configuration script created to provide better security for your server while giving you an easy to use, advanced interface for managing your firewall settings. CSF configures your server’s firewall to lock down public access to services and only allow certain connections, such as logging in to FTP, checking your email, or loading your websites.

ConfigServe Firewall also comes with a service called Login Failure Daemon, or LFD. LFD watches your user activity for excessive login failures which are commonly seen during brute force attacks. LFD also blocks IPs if a huge number of failed logins are appearing from that IP. The block is temporary. It also allows the admin to view the blocked IP by enabling an email alert service.
Some of the features include:
-Login Tracking
-Process Tracking
-Directory Watching
-Advanced Allow/Deny features
-Block Reporting
-Port Flood Protection

Lets start the Instalaltion of CSF:
Step 1: Login to your server via SSH and follows the commands to download and install the CSF on your server.
Step 2: Execute the below commands one by one as mentioned below

# cd /usr/src
# rm -fv csf.tgz
# wget https://download.configserver.com/csf.tgz
# tar -xzf csf.tgz
# cd csf
# sh install.sh

Installation will get completed, Your server is inatalled by CSF then you need to configure it as you required.

I hope this article will helps you!!
Done!