A firewall protects your LAN from the outside world while filtering packets and allowing selected Internet or WAN traffic through.

What is a firewall, iptables, ports, NAT, IP forwarding

Linux Firewall – What is a firewall, iptables, ports, NAT, IP forwarding

Setting up a firewall using a script

How to setup a Linux firewall using a script and iptables

Stop iptables logging to console

How to stop iptables logging to the console