ModSecurity, often referred to as Modsec, is a free, open-source web application firewall (WAF). ModSecurity was created as a module for the Apache HTTP Server and also exists for Nginx. In the following tutorial, you will learn how to install WAF on Ubuntu 22.04 LTS.

Source: LXer – How to Install Nginx with ModSecurity 3 on Ubuntu 22.04 LTS