RHEL7 FTP server error: ftp: connect: No route to host solution - LinuxConfig.org

When setting up FTP server on Redhat 7 Linux box the following error message ftp: connect: No route to host may pop-up during FTP client session:
This is a companion discussion topic for the original entry at https://linuxconfig.org/rhel7-ftp-server-error-ftp-connect-no-route-to-host-solution