实验环境为CentOS7.5

[root@localhost ~]# systemctl disable firewalld #禁用防火墙

Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@localhost ~]# systemctl enable firewalld 	#启用防火墙,开机启动

Created symlink from /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service to /usr/lib/systemd/system/firewalld.service.
Created symlink from /etc/systemd/system/multi-user.target.wants/firewalld.service to /usr/lib/systemd/system/firewalld.service.
[root@localhost ~]# systemctl stop firewalld 	#关闭防火墙

[root@localhost ~]# systemctl start firewalld	#启动防火墙

[root@localhost ~]# systemctl restart firewalld	#重启防火墙

[root@localhost ~]# systemctl status firewalld	#查看防火墙状态

● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: active (running) since 一 2019-10-28 10:02:07 CST; 1min 13s ago
     Docs: man:firewalld(1)
 Main PID: 3101 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─3101 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

10月 28 10:02:07 localhost.localdomain systemd[1]: Starting firewalld - dynamic firewall daemon...
10月 28 10:02:07 localhost.localdomain systemd[1]: Started firewalld - dynamic firewall daemon.
[root@localhost ~]# firewall-cmd --zone=public --add-port=80/tcp --permanent	#允许80端口tcp协议通过防火墙

[root@localhost ~]# firewall-cmd –reload #更新防火墙规则

success	
[root@localhost ~]# firewall-cmd --zone=public --query-port=80/tcp #查看80端口

yes
[root@localhost ~]# firewall-cmd --zone=public --list-ports #查看所有打开端口

80/tcp
[root@localhost ~]# firewall-cmd --zone=public --remove-port=80/tcp --permanent	#删除端口

success