Redis无法访问，4种原因：host ip不对，密码不对，端口号未开放，protected-mode 保护模式下远程访问

今天，本地连接远程服务器上的Redis，一直失败。

redis.clients.jedis.exceptions.JedisException: Could not get a resource from the pool     at redis.clients.util.Pool.getResource(Pool.java:51)     at redis.clients.jedis.JedisPool.getResource(JedisPool.java:226)     at com.kakarote.crm9.common.config.redis.JedisImpl.getJedis(JedisImpl.java:1304)

之前遇到过的几种情况，先排查下：

ip是否正确，输错了，还是不行。

密码，没有设置，还是不行。

检查服务器端口号，是否开放了，确实打开了。

用本地起了Redis，正常访问，所以怀疑是 不让远程访问。

研究了下，初步结论，没验证

1、bind 绑定ip

由于自己的ip，不稳定，不太好用

2、关闭保护模式

3、默认配置不懂，增加密码

最后，觉得都麻烦，所以为了长期安全发展，还是只让本地ip访问吧。

本地开发时，启动本地Redis。

#bind 127.0.0.1
70
71 # Protected mode is a layer of security protection, in order to avoid that
72 # Redis instances left open on the internet are accessed and exploited.
73 #
74 # When protected mode is on and if:
75 #
76 # 1) The server is not binding explicitly to a set of addresses using the
77 # "bind" directive.
78 # 2) No password is configured.
79 #
80 # The server only accepts connections from clients connecting from the
81 # IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from Unix domain
82 # sockets.
83 #
84 # By default protected mode is enabled. You should disable it only if
85 # you are sure you want clients from other hosts to connect to Redis
86 # even if no authentication is configured, nor a specific set of interfaces
87 # are explicitly listed using the "bind" directive.
88 protected-mode yes
89
90 # Accept connections on the specified port, default is 6379 (IANA #815344).
91 # If port 0 is specified Redis will not listen on a TCP socket.
92 port 6379

结论，如果你无法访问redis，检查4个方面

1、host ip不对，

2、密码不对

3、服务器端口号未开放

4、保护模式下远程访问