How to close certain TCP/UDP ports (incoming) for ALL networks except listed through IPTABLES.
I have a small set of NETWORKS I'd like to leave THE ports to be open. But want to close for all other networks.
Simply put an ACCEPT rule before you DROP/REJECT. For example
will allow connection to TCP port 80 from 192.168.1.0/24 network while dropping all other connections to the port.
Set accept rules for all of the traffic that you want to allow through and then have a deny rule for everything else.
Allows traffic to port 80 and rejects everything else.