iptables: what happen after a reboot?

Installing NCPA for nagios, I found these instructions iptables -I INPUT -p tcp --destination-port 5693 -j ACCEPT apt-get install -y iptables-persistent Answer yes to saving existing rules Of course, I cannot save ALL ruleset. Because I am using failban and actually my iptables ruleset is veeeery big. I'd like to persist only iptables -I INPUT -p tcp --destination-port 5693 -j ACCEPT Is it possible? Is still really needed to use iptables-persistent to keep firewall rules? I have a doubt because I am using port 80 and a few others without any problems after system reboots... So, When I reboot the system, will normally iptables reset all rules? If yes Why ? If no .. wel...