How to install CSF (ConfigServer Security & Firewall) with DirectAdmin or WHM
Block IPs with Brute Force Monitor in DirectAdmin using CSF
Source: https://help.poralix.com/articles/how-to-block-ips-with-csf-directadmin-bfm
Regular install of CSF
cd /usr/local/src wget http://www.configserver.com/free/csf.tgz tar -xzf csf.tgz cd csf ./install.directadmin.sh
Now login as Admin into directadmin or WHM, and click the link ConfigServer Security & Firewall
You'll probably want to add your WAN IP here--you can find out what it is here: http://www.ip-secrets.com/
Then add your WAN IP into Quick Allow column.