Net-filter as we all know it’s a firewall in Linux. Firewalld is a dynamic daemon to manage firewalls with support for network zones. In the earlier version, RHEL & CentOS 6 we have been using iptables as a daemon for packet filtering framework. In RHEL/CentOS 7/8 and Fedora iptables interface is being replaced by firewalld.
Firewalls - DesignLinux
How to Open Port for a Specific IP Address in Firewalld
How can I allow traffic from a specific IP address in my private network or allow traffic from a specific private network through firewalld, to a specific port or service on a Red Hat Enterprise Linux (RHEL) or CentOS server? In this short article, you will learn how to open a port for a specific