Best three useful firewall-cmd command on centos 7

remove public zone service:
firewall-cmd –zone=public –remove-service=ssh –permanent
firewall-cmd –reload

add ip range to trusted zone and add ssh service to trusted zone

firewall-cmd –permanent –zone=”trusted” –add-source=”123.51.11.2/32″
firewall-cmd –permanent –zone=”trusted” –add-service=”ssh”
firewall-cmd –reload
firewall-cmd –list-all-zones

add anthor ip range to trusted zone

firewall-cmd –permanent –zone=”trusted” –add-source=”172.30.30.0/24″
firewall-cmd –reload
firewall-cmd –list-all-zones