[參考]Linux IPTables Rules Examples

25 Most Frequently Used Linux IPTables Rules Examples
http://crm.vpscheap.net/knowledgebase.php?action=displayarticle&id=29

Linux IPTables: Incoming and Outgoing Rule Examples (SSH and HTTP)
http://www.thegeekstuff.com/2011/03/iptables-inbound-and-outbound-rules/

How to Log Linux IPTables Firewall Dropped Packets to a Log File
http://www.thegeekstuff.com/2012/08/iptables-log-packets/