Image Source: techmint Useful firewall-cmd Examples (Source: thegreekdiary.com) 1. List all zones Use the following command to list information for all zones. Only partial output is displayed. firewall-cmd --list-all-zones Output: work target: default icmp-block-inversion: no interfaces: sources: services: dhcpv6-client ssh ports: protocols: masquerade: no forward-ports: sourceports: icmp-blocks: rich rules: drop target: DROP icmp-block-inversion: no interfaces: sources: services: ports: protocols: masquerade: no forward-ports: sourceports: icmp-blocks: rich rules: ..... Public is the default zone set, if you do not change it. To check the currently set default zone use the below command: firewall-cmd --get-default-zone public 2. List allowed service and ports on the system To show currently allowed service on your system use ...