Centos7/RHEL7 FirewallD -- the least you need to know

This post is just a simple hints-tips to get something going with FirewallD without going into too much detail.

  1. Checking if you are using firewalld:
    • firewall-cmd --state
  2. Check your zones (needed later when opening ports):
    • firewall-cmd --get-default-zone
    • firewall-cmd --get-active-zones
  3. Checking what is active:
    • firewall-cmd --zone=public --list-all
  4. Opening services:
    • firewall-cmd --zone=public --add-service=http Or alternatively:
    • firewall-cmd --permanent --zone=public --add-service=http
    • firewall-cmd --reload Services are defined in /usr/lib/firewalld/services and /etc/firewalld/services.
  5. Opening ports:
    • firewall-cmd --permanent --zone=public --add-port=443/tcp
    • firewall-cmd --reload