LEMP (also known as LNMP) is a group of open-source software which enable a server to host dynamic websites and web applications. It consists of the Linux operating system, the (E)Nginx web server (which replaces the Apache component of a LAMP stack), the MySQL relational database management system, and the PHP programming language.
WordPress is a very robust content-management system (CMS) that is free and open source. Because anyone can comment, create an account, and post on WordPress, many malicious actors have created networks of bots and servers that compromise and spam WordPress sites through brute-force attacks.
Fail2Ban is an intrusion prevention software framework that protects computer servers from brute-force attacks. Written in the Python programming language, it is able to run on POSIX systems that have an interface to a packet-control system or firewall installed locally.
Note: In this guide, we will be using version 0.9.6 of Fail2ban on an Debian 9.4 server, but most of it should apply to other distributions as well.