centos如何打开端口？

systemctl start firewalld

systemctl stop firewalld

systemctl enable firewalld

sytemctl disable firewalld

firewall-cmd --reload

systemctl status firewalld或者 firewall-cmd --state

firewall-cmd --version

firewall-cmd --help

firewall-cmd --get-active-zones

firewall-cmd --get-zone-of-interface=eth0

firewall-cmd --panic-on

firewall-cmd --panic-off

firewall-cmd --query-panic

firewall-cmd --zone=public --add-interface=eth0(永久生效再加上 --permanent 然后reload防火墙)

firewall-cmd --set-default-zone=public(立即生效，无需重启)

firewall-cmd --reload或firewall-cmd --complete-reload(两者的区别就是第一个无需断开连接，就是firewalld特性之一动态

添加规则，第二个需要断开连接，类似重启服务)

firewall-cmd --zone=public --list-ports

firewall-cmd --zone=public --add-port=80/tcp(永久生效再加上 --permanent)