FirewallD
Reference for FirewallD, the dynamic firewall manager for Linux that uses zones and services on top of nftables. Covers zones, services, ports, rich rules, NAT, ICMP filtering, and troubleshooting.
Nftables
NFTables
Reference for the nftables packet filtering framework: address families, tables, chains, rules, sets and maps, NAT, rate limiting, rule management, and migration from iptables.