java.net.ConnectException: Connection timed out (Connection timed out)

Question

项目布置到Linux服务器上，能正常连接数据库(Windows服务器的)，不能发送请求给别的地址，连接不到外部Windows服务器上的redis和MongoDB

java.net.ConnectException: Connection timed out (Connection timed out)
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:117)
    at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:177)
    at org.apache.http.impl.conn.ManagedClientConnectionImpl.open(ManagedClientConnectionImpl.java:304)
    at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:611)
    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:446)
    at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:863)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:106)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:57)
    at com.sinosoft.ops.technologyelite.util.aliyun.HttpUtils.doPost(HttpUtils.java:101)

使用Linux切换数据库时出现的这个看不太明白（想到既然redis跟MongoDB连不上就全换本地），有没有高解释一下什么意思。

回归正题，由于使用的Linux环境是内网的，想链接外部的redis和MongoDB是不是不可能的？ 如果想让项目正常运行是不是只能连接Linux本地的redis和MongoDB？

Answer 1

内网访问外网是没问题，可能是linux的防火墙问题，也可能是linux没有请求外网的权限