FirewallD is a dynamic firewall management tool used on modern Linux distributions such as AlmaLinux, Rocky Linux, CentOS, and RHEL. It provides an easy way to manage iptables and nftables rules using zones, services, ports, and rich rules. FirewallD is widely used in VPS hosting environments, dedicated servers, and enterprise Linux systems to secure network traffic and control inbound and outbound connections.
1. Check Firewall Status
sudo firewall-cmd --statesudo→ Runs the command with administrative privileges.--state→ Displays whether FirewallD is running.
2. Start FirewallD
sudo systemctl start firewalldsystemctl→ Controls systemd services.start→ Starts the FirewallD service.firewalld→ Firewall service name.
3. Enable FirewallD at Boot
sudo systemctl enable firewalldenable→ Starts FirewallD automatically at boot.
4. List Active Zones
sudo firewall-cmd --get-active-zones--get-active-zones→ Displays active firewall zones.
5. List All Rules in Current Zone
sudo firewall-cmd --list-all--list-all→ Shows services, ports, and settings in the active zone.
6. Add HTTP Service Permanently
sudo firewall-cmd --permanent --add-service=http--permanent→ Makes rule persistent after reboot.--add-service=http→ Opens HTTP (port 80).
7. Add HTTPS Service
sudo firewall-cmd --permanent --add-service=https--add-service=https→ Opens HTTPS (port 443).
8. Open a Custom Port
sudo firewall-cmd --permanent --add-port=8080/tcp--add-port=8080/tcp→ Opens TCP port 8080.
9. Remove a Port
sudo firewall-cmd --permanent --remove-port=8080/tcp--remove-port=8080/tcp→ Closes TCP port 8080.
10. Reload FirewallD
sudo firewall-cmd --reload--reload→ Applies configuration changes.
11. Allow SSH Service
sudo firewall-cmd --permanent --add-service=ssh--add-service=ssh→ Opens SSH (default port 22).
12. Change Default Zone
sudo firewall-cmd --set-default-zone=public--set-default-zone=public→ Sets the default firewall zone.
13. Assign Interface to Zone
sudo firewall-cmd --zone=public --change-interface=eth0--zone=public→ Specifies the firewall zone.--change-interface=eth0→ Assigns network interface to zone.
14. Allow IP Address
sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="1.2.3.4" accept'--add-rich-rule→ Adds advanced firewall rule.source address="1.2.3.4"→ Specifies allowed IP address.accept→ Allows traffic.
15. Block an IP Address
sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="5.6.7.8" reject'reject→ Blocks traffic from the specified IP.
16. Enable Masquerading (NAT)
sudo firewall-cmd --permanent --add-masquerade--add-masquerade→ Enables network address translation.
17. Forward a Port
sudo firewall-cmd --permanent --add-forward-port=port=80:proto=tcp:toport=8080--add-forward-port→ Adds port forwarding rule.port=80→ Incoming port.proto=tcp→ Protocol used.toport=8080→ Destination port.
18. List Available Services
sudo firewall-cmd --get-services--get-services→ Displays predefined services.
19. Remove a Service
sudo firewall-cmd --permanent --remove-service=http--remove-service=http→ Closes HTTP service.
20. Panic Mode (Block All Traffic)
sudo firewall-cmd --panic-on--panic-on→ Immediately blocks all incoming and outgoing traffic.
21. Disable Panic Mode
sudo firewall-cmd --panic-off--panic-off→ Restores normal firewall operation.
22. Check Open Ports
sudo firewall-cmd --list-ports--list-ports→ Displays currently open ports.
Why FirewallD Is Essential for Linux Server Security
FirewallD simplifies firewall management for Linux VPS hosting, cloud servers, and enterprise systems. With support for zones, rich rules, NAT, port forwarding, and service-based configuration, it provides flexible and secure network traffic control. Proper FirewallD configuration is critical for protecting web servers, database servers, SSH access, and custom applications.
Final thoughts
These useful FirewallD examples demonstrate how to manage Linux firewall rules efficiently and securely. Whether you are configuring a VPS, protecting a production web server, or setting up advanced port forwarding, mastering FirewallD is essential for modern Linux system administration. A properly configured firewall greatly improves security, reduces attack surface, and ensures reliable network performance.
