The firewalld service provides multiple ways with which to configure rules, including regular rules and direct rules.

One difference between these is how each method interacts with the underlying packet-filtering framework (iptables or nftables).

The direct rules are advanced, low-level rules that allow direct interaction with iptables. However, the iptables component is unmaintained and will be removed from a future major RHEL version. Therefore, replace firewalld direct rules with nftables.