How to prevent unauthorized users from connecting to ProxySQL (opens in new tab)

ProxySQL is a great load balancer which however suffers from some shortcomings concerning the management of MySQL users. ProxySQL provides a firewall which, in my case, is not complete enough to properly manage users and secure their access. Indeed, this firewall does not accept subnets and keeps unauthorized connections in ProxySQL. We cannot then be sure of not suffering a DDOS attack on our ProxySQL instance. In this article, I will explain how I managed to overcome this problem.