FatDog uses eztables as a "frontend" for iptables, which is supposed to be easy to configure (but not entirely clear to me... )
https://github.com/louwrentius/eztables
The problem is once you have eztables started and running, FatDog will ignore generic iptables rules entered from the command line. So it looks like you have to make your configuration in eztables.cfg.
How would you translate the following rule into "eztables speak"?
iptables -A INPUT -s 192.168.100.1 -j DROP
Thanks for your feedback!