Savannah W-ITS

GEO Blocking network access – blocking specific IP blocks (GEO-blocking – do you really need those connections from Asia?)
CAVEAT: The flow of packets through your system is fairly complex – I am limiting this discussion and I encourage you to RTM as well as the tutorial referenced in below…
There are a number of approaches to [...]

Part 101b:  Some example rules for your Linux Firewall

Creating a custom chain
Creating a LOG rule
Creating a  DROP rule

Some basic/simple rules you should implement – blocking RFC 1918 (or similar) traffic at your gateway.
Your Internet Gateway is the connection between your internal network and the public Internet.  For many consumers and small businesses this is [...]

Part 101a: Where should you start with a Linux firewall?
Review your configuration (review ALL tables – save the short script below to the file /tmp/show.firewall – you must be ‘root’ or use ’sudo’)
#!/bin/bash
for TABLE in raw mangle nat filter
do
printf “\t##### Table: ${TABLE} ####\n”
iptables [...]