Iptables:
1- Netfilter/iptables project homepage - Documentation about the netfilter/iptables project:
http://www.netfilter.org/documentation/index.html
2- Iptables.info:
http://www.iptables.info/en/iptables-contents.html
3- Tutorial iptables:
https://www.frozentux.net/iptables-tutorial/iptables-tutorial.html
4- Linux Firewall Tutorial: IPTables Tables, Chains, Rules Fundamental:
www.thegeekstuff.com/2011/01/iptables-fundamentals/
5- Iptables Howto:
https://help.ubuntu.com/community/IptablesHowTo
6- Imprescindible: estructura d'iptables
http://www.iptables.info/en/structure-of-iptables.html
