This is to document a problem I had with CSF (ConfigServer Firewall) today that cost me a good couple hours.
The problem was that my Ethereum node communicating on port 30303 was being blocked, even though I had added the ports to my config file. It seemed to be working just fine, blocking bad logins and otherwise communications to and from my machine, but when I added new ports to the TCP_IN, TCP_OUT, UDP_IN and UDP_OUT lists and ran
sudo systemctl restart csf, they wouldn't take effect.
See answer for solution....