Redhat 8 open FTP port 21 with firewalld - LinuxConfig.org

This article explains how to open FTP port 21 on Red Hat Enterprise Linux 8 system with the firewalld firewall. The FTP protocol is primarily used by file transfer services such as, but not limited to, vsftpd FTP server.
This is a companion discussion topic for the original entry at https://linuxconfig.org/redhat-8-open-ftp-port-21-with-firewalld