How to use iptables to configure IP address whitelist under centOS7

http://www.jb51.net/article/98625.htm

Super detailed iptables introduction
http://blog.csdn.net/sdytlm/article/details/6544913/


Open a range of ports 3000 to 5000

-A RH- Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 3000:5000 -j ACCEPT
http://blog.csdn.net/kobe_lzq/article/details/7977013


An error is reported when starting iptables : iptables: No config file.
1. Enter the following command:
iptables -P OUTPUT ACCEPT
service iptables save
to save and start the firewall