美国VPS查询redis防火墙的示例：

[root@localhost demo]# 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 三 2019-03-06 00:56:15 PST; 2min 43s ago

Docs: man:firewalld(1)

Main PID: 630 (firewalld)

CGroup: /system.slice/firewalld.service

└─630 /usr/bin/python -Es /usr/sbin/firewalld –nofork –nopid

3月 06 00:56:14 localhost.localdomain systemd[1]: Starting firewalld – dynamic fir….

3月 06 00:56:15 localhost.localdomain systemd[1]: Started firewalld – dynamic fire….

Hint: Some lines were ellipsized, use -l to show in full.