CentOS7 端口的开放关闭查看都是用防火墙来控制的，具体命令如下：
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查看防火墙状态：（active (running) 即是开启状态）
systemctl status firewalld
[root@WSS bin]# systemctl status firewalld ● firewalld.service - firewalld - dynamic firewall daemon Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled) Active: active (running) since 四 2019-07-11 09:37:11 CST; 7h ago Docs: man:firewalld(1) Main PID: 44370 (firewalld) Tasks: 2 CGroup: /system.slice/firewalld.service └─44370 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete FORWARD...hain?). 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete FORWARD...hain?). 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete FORWARD...hain?). 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete FORWARD...t name. 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete FORWARD...t name. 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete INPUT -...hain?). 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete INPUT -...hain?). 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete OUTPUT ...hain?). 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete INPUT -...hain?). 7月 11 09:37:13 WSS firewalld[44370]: WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -w --table filter --delete INPUT -...hain?). Hint: Some lines were ellipsized, use -l to show in full. [root@WSS bin]#
查看已开放端口：
firewall-cmd --list-all
防火墙开放端口：（开放端口后需重载防火墙）
firewall-cmd --zone=public --add-port=3306/tcp --permanent
firewall-cmd --reload
firewalld的基本使用
启动： systemctl start firewalld
关闭： systemctl stop firewalld
查看状态： systemctl status firewalld
开机禁用 ： systemctl disable firewalld
开机启用 ： systemctl enable firewalld
systemctl是CentOS7的服务管理工具中主要的工具，它融合之前service和chkconfig的功能于一体。
启动一个服务：systemctl start firewalld.service
关闭一个服务：systemctl stop firewalld.service
重启一个服务：systemctl restart firewalld.service
显示一个服务的状态：systemctl status firewalld.service
在开机时启用一个服务：systemctl enable firewalld.service
在开机时禁用一个服务：systemctl disable firewalld.service
查看服务是否开机启动：systemctl is-enabled firewalld.service
查看已启动的服务列表：systemctl list-unit-files|grep enabled
查看启动失败的服务列表：systemctl --failed