最近利用Apache Mina实现了一个http服务，发布到linux下发现无法访问，通过HttpClient来发送http请求时，报如下错误：
Exception in thread "main" org.apache.http.conn.HttpHostConnectException: Connection to http://10.5.20.96:8011 refused
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:190) at org.apache.http.impl.conn.ManagedClientConnectionImpl.open(ManagedClientConnectionImpl.java:294) at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:640) at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:479) at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906) at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:1066) at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:1044) at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:1035) at com.tudou.findlabel.entrance.ClientWithResponseHandler.main(ClientWithResponseHandler.java:52)Caused by: java.net.ConnectException: Connection refused: connect at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:519) at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:127) at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:180) ... 8 more原来是因为linux下没有开启对8011的端口访问权限造成的。通过下面的命令可以开启允许对外访问的网络端口：
步骤一：打开Linux文件：
/etc/csf/csf.conf
修改：
# Allow incoming TCP ports
TCP_IN = "20,21,22,25,53,80,110,143,443,465,587,993,995,3690,3306,8080,8086,8088"# Allow outgoing TCP ports
TCP_OUT = "20,21,22,25,53,80,110,113,443,993,995,3690,3306,8080,8086,8088"
步骤二：
/sbin/iptables -I INPUT -p tcp --dport 8086 -j ACCEPT #开启8086端口
/etc/rc.d/init.d/iptables save #保存配置
/etc/rc.d/init.d/iptables restart #重启服务
步骤三：
查看端口是否已经开放
/etc/init.d/iptables status
结果如下
步骤四：
重启相关web服务即可！