![]() The firewalld subsystem, available from the firewalld RPM package, is not included in a minimal install, but is included in a base installation. With firewalld, firewall management is simplified by classifying all network traffic into zones. ![]() Based on criteria such as the source IP address of a packet or the incoming network interface, traffic is diverted into the firewall rules for the appropriate zone. Each zone has its own list of ports and services that are either open or closed. Note: For laptops or other machines that regularly change networks, NetworkManager can be used to automatically set the firewall zone for a connection. The zones are customized with rules appropriate for particular connections. This is especially useful when traveling between home, work, and public wireless networks. ![]() A user might want their system’s sshd service to be reachable when connected to their home and corporate networks, but not when connected to the public wireless network in the local coffee shop.įirewalld checks the source address for every packet coming into the system. If that source address is assigned to a specific zone, the rules for that zone apply. If the source address is not assigned to a zone, firewalld associates the packet with the zone for the incoming network interface and the rules for that zone apply. If the network interface is not associated with a zone for some reason, then firewalld associates the packet with the default zone. The default zone is not a separate zone, but is a designation for an existing zone. Initially, firewallddesignates the public zone as default, and maps the lo loopback interface to the trusted zone. Most zones allow traffic through the firewall, which matches a list of particular ports and protocols, such as 631/udp, or pre-defined services, such as ssh. If the traffic does not match a permitted port and protocol or service, it is generally rejected. ![]() (The trusted zone, which permits all traffic by default, is one exception to this.) Pre-defined Zonesįirewalld has pre-defined zones, each of which you can customize. By default, all zones permit any incoming traffic which is part of a communication initiated by the system, and all outgoing traffic. Default Configuration of Firewalld Zones ZONE NAME The following table details these initial zone configuration. ![]()
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