今天在项目中连接远程redis时，抛出连接超时异常：connect timed out。

详细信息例如以下：

org.springframework.data.redis.connection.PoolException: Could not get a resource from the pool; nested exception is io.lettuce.core.RedisConnectionException: Unable to connect to 192.168.xxx.xxx:6379
	at org.springframework.data.redis.connection.lettuce.LettucePoolingConnectionProvider.getConnection(LettucePoolingConnectionProvider.java:109) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$SharedConnection.getNativeConnection(LettuceConnectionFactory.java:1198) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$SharedConnection.getConnection(LettuceConnectionFactory.java:1179) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory.getSharedConnection(LettuceConnectionFactory.java:942) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory.getConnection(LettuceConnectionFactory.java:353) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.core.RedisConnectionUtils.doGetConnection(RedisConnectionUtils.java:132) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:95) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:82) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:215) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:188) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.core.AbstractOperations.execute(AbstractOperations.java:96) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at org.springframework.data.redis.core.DefaultValueOperations.set(DefaultValueOperations.java:236) ~[spring-data-redis-2.2.1.RELEASE.jar:2.2.1.RELEASE]
	at com.hust.security.filter.TokenLoginFilter.successfulAuthentication(TokenLoginFilter.java:76) ~[classes/:na]
	at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:240) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:92) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:77) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) ~[spring-security-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1579) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_144]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_144]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.27.jar:9.0.27]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_144]
Caused by: io.netty.channel.ConnectTimeoutException: connection timed out: /192.168.xxx.xxx:6379
	at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe$1.run(AbstractNioChannel.java:261) ~[netty-transport-4.1.43.Final.jar:4.1.43.Final]
	at io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98) ~[netty-common-4.1.43.Final.jar:4.1.43.Final]
	at io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:150) ~[netty-common-4.1.43.Final.jar:4.1.43.Final]
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163) ~[netty-common-4.1.43.Final.jar:4.1.43.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:510) ~[netty-common-4.1.43.Final.jar:4.1.43.Final]
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:518) ~[netty-transport-4.1.43.Final.jar:4.1.43.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor$6.run(SingleThreadEventExecutor.java:1050) ~[netty-common-4.1.43.Final.jar:4.1.43.Final]
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.43.Final.jar:4.1.43.Final]
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.43.Final.jar:4.1.43.Final]
	... 1 common frames omitted

尝试使用windows测试 ，ping IP 成功。但是依旧是Connection: Connection error: Connection timed out
于是怀疑是redis server防火墙没关闭。
查看server防火墙状态：

service iptables status

关闭防火墙：

service iptables stop

然后再进行连接，这次就非常快连接成功了。问题解决。