Red Hat's firewalld is a firewall management utility that comes on all Red Hat-type Linux distros such as CentOS, AlmaLinux, Rocky Linux, Oracle Enterprise Linux, and Fedora. It's also available as an option for certain other Linux distros, such as Ubuntu. The reason that firewalld has been such a mystery is that Red Hat has never documented how it really works under the hood. Never fear, the BeginLinux Guru is here to clear up the mystery for all you aspiring Linux administration folk. Thank you for watching this Linux tutorial about Linux commands. Purchase links for "Mastering Linux Security and Hardening": Packt Publishing link: https://www.packtpub.com/product/mastering-linux-security-and-hardening-third-edition/9781837630516 Amazon link: https://amzn.to/3ZdIR7Y