ConfigServer Security & Firewall is available here
The most popular software for any server is ConfigServer Security & Firewall (CSF) which is used on thousands of VPS hosted by The-Online.com and other hosting companies around the world. You can download free CSF from Github repository here.
They’ve released csf (ConfigServer Security & Firewall), cmc (Configserver Modsecurity Control, for cPanel), cmm (ConfigServer Mail Manage, for cPanel), cmq (ConfigServer Mail Queues, for cPanel and DirectAdmin), and cse (ConfigServer Explorer, for cPanel) under the GPLv3 license and all are available to download from github using above link.
ConfigServer Mail Manage (csm), CS Mail Queues (cmq), CS Modsecurity Control (cmc), CS Explorer (cse) and ConfigServer Security & Firewall (csf) will continue to work forever!