How To List and Delete Iptables Firewall Rules | DigitalOcean https://www.digitalocean.com/community/tutorials/how-to-list-and-delete-iptables-firewall-rules
Iptables Essentials: Common Firewall Rules and Commands | DigitalOcean https://www.digitalocean.com/community/tutorials/iptables-essentials-common-firewall-rules-and-commands
How To Set Up a Firewall Using Iptables on Ubuntu 14.04 | DigitalOcean https://www.digitalocean.com/community/tutorials/how-to-set-up-a-firewall-using-iptables-on-ubuntu-14-04
How To Choose an Effective Firewall Policy to Secure your Servers | DigitalOcean https://www.digitalocean.com/community/tutorials/how-to-choose-an-effective-firewall-policy-to-secure-your-servers
The Beginner’s Guide to iptables, the Linux Firewall http://www.howtogeek.com/177621/the-beginners-guide-to-iptables-the-linux-firewall/
25 Most Frequently Used Linux IPTables Rules Examples http://www.thegeekstuff.com/2011/06/iptables-rules-examples/