• Enable CSF firewall for WHM Resellers
• open3: exec of /usr/sbin/ipset flush failed at /usr/sbin/csf line 4752.

Install CSF Firewall

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

Now login to WHM > Plugins to configure CSF firewall.