Linux Administration Cookbook

firewall-cmd

Firewalld (the daemon controlled by firewall-cmd) introduces the concept of zones to the Linux firewall.

Zones are assigned to specific interfaces, with specific rules configured per zone.

You can list the currently configured zones using firewall-cmd, too:

$ sudo firewall-cmd --get-zonesblock dmz drop external home internal public trusted work

To check which zone we're actively using, and on which interface, we use --get-active-zones.

In the following code, we can see that eth0 and eth1 are using the public zone:

$ firewall-cmd --get-active-zonespublic interfaces: eth0 eth1

eth2 is also under the public zone, but the interface is unconfigured, thus, inactive.

Because eth0 is active under public, let's list the details of the ...