防火牆狀態查看、開啓、關閉
systemctl status firewalld.service
systemctl start firewalld.service
systemctl stop firewalld.service
注:systemctl start firewalld 與 systemctl start firewalld.service 執行的結果一致
開放指定端口
firewall-cmd --permanent --zone=public --add-port=9999/tcp
firewall-cmd --reload
解除指定端口開放
firewall-cmd --zone=public --remove-port=9999/tcp --permanent
firewall-cmd --reload
查看目前已經開放的端口列表
firewall-cmd --zone=public --list-ports