Check server setup

Centos Release
rpm -q centos-release

FirewallD
firewall-cmd –zone=public –list-all

refs:
https://linuxconfig.org/how-to-check-centos-version
https://www.liquidweb.com/kb/an-introduction-to-firewalld/
https://www.tecmint.com/firewalld-rules-for-centos-7/