redis3.2版本后新增protected-mode配置，默认是yes，即开启。设置外部网络连接redis服务，设置方式如下：
1、关闭protected-mode模式，此时外部网络可以直接访问
2、开启protected-mode保护模式，需配置bind ip或者设置访问密码
如果开启保护模式 ，而未配置bind 会报一下错误
DENIED Redis is running in protected mode because protected mode is enabled,
no bind address was specified, no authentication password is requested to clients.
In this mode connections are only accepted from the loopback interface.
If you want to connect from external computers to Redis you may adopt one of the following solutions:
1) Just disable protected mode sending the command 'CONFIG SET protected-mode no' from the loopback
interface by connecting to Redis from the same host the server is running, however MAKE SURE Redis
is not publicly accessible from internet if you do so. Use CONFIG REWRITE to make this change permanent.
2) Alternatively you can just disable the protected mode by editing the Redis configuration file,
and setting the protected mode option to 'no', and then restarting the server.
3) If you started the server manually just for testing, restart it with the '--protected-mode no' option.
4) Setup a bind address or an authentication password. NOTE: You only need to do one of the above
things in order for the server to start accepting connections from the outside.