When doing some changes in iptables, one can save before so one can restore if something go wrong.

SAVE

iptables-save > /root/working.iptables.rules

RESTORE

iptables-restore < /root/working.iptables.rules

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After rules are changed and one is happy with it, it needs to be saved to survive reboot. On CentOS, its done by command "service iptables save" or "iptables-save > /etc/sysconfig/iptables"