[ Thanks to Dennis G.
Allard for this link. ]
“The firewall that the Red Hat installer set up for me
in response to my request for a high level of security was too
restrictive. And, I couldn’t find any GUI tool in either GNOME or
KDE to reconfigure the firewall. For example, the KDE menu item for
editing my firewall showed an empty set of rules even though this
file and the above startup script existed. So I had no confidence
in the GUI firewall tools, hence my decision to edit this file
manually.”