This is my setup. I want to block the access to the internet for a certain subnet ( 192.168.200.X). I still want to be able to access my internal Webserver. I tried blocking the subnet by adding:
iptables -I INPUT -s 192.168.200.0/255.255.255.0 -j DROP
But it isn’t working.
Have you tried adding that to the FORWARD chain rather than INPUT?