Programs
firewall-cmd
firewalld command line client
View firewall state
firewall-cmd --state
--state — Check whether firewall daemon is active.
View active zones
firewall-cmd --get-active-zones
--get-active-zones — Print currently active zones with interfaces and sources used.
View rules
firewall-cmd --zone=public --list-all
--zone=public — Name of the zone.
--list-all — View everything added or enabled for zone.
Open port
firewall-cmd --zone=public --add-port=80/tcp --permanent
--zone=public — Name of the zone.
--add-port=80/tcp — Add port to the zone.
--permanent — Save changes permanently.
Reload firewall
firewall-cmd --reload
--reload — Reload firewall rules.
systemctl
Control the systemd system and service manager.
Reload service
systemctl reload sshd.service