TecMint published a tutorial about configuring FirewallD in RHEL, CentOS and Fedora.
How to Configure FirewallD in RHEL, CentOS and Fedora
In iptables, we used to configure as INPUT, OUTPUT & FORWARD CHAINS but here in Firewalld, there are different zones available, which will be discussed.
How to Configure FirewallD in RHEL, CentOS and Fedora