Firewalld provides a dynamically managed firewall with support for 
network/firewall zones that define the trust level of network 
connections or interfaces. It has support for IPv4, IPv6 firewall 
settings, ethernet bridges and IP sets. There is a separation of 
runtime and permanent configuration options. It also provides an 
interface for services or applications to add firewall rules directly.

It uses the nftables backend by default, iptables can be used, but
is deprecated. ebtables support can be enabled at compile-time.