Redhat : IPTABLES : How to persist iptables as its changes are not saved by default

https://www.geeksforgeeks.org/iptables-restore-command-in-linux-with-examples/

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/4/html/security_guide/s2-firewall-ipt-act-sav

7.2.2. SAVING AND RESTORING IPTABLES RULES

Firewall rules are only valid for the time the computer is on; so, if the system is rebooted, the rules are automatically flushed and reset. To save the rules so that they are loaded later, use the following command:

/sbin/service iptables save

The rules are stored in the file /etc/sysconfig/iptables and are applied whenever the service is started or restarted, including when the machine is rebooted.