Hi friends i am using Opensuse 42.3 but i cannot find the “FIREWALL-CMD” also i searched the forums and didnt find anything related, any clue why? or is “firewall-cmd” is not supported by OpenSUSE? 
Normally openSUSE uses SuSEfirewall2 (note the archaic spelling).
During installation it is by default switched on. Thus unless you changed that during installation, it is most probably already running as a so called “personal firewall”.
As many system configurations, you can use YaST to configure it.
YaST > Security and Users > Firewall
HTH