SQL Server无法以local 登陆问题的解决方法provider: Named Pipes Provider, error: 40 - Could not open a connection_the server is connected from local

错误信息的内容如下：

TITLE: Connect to Server
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Cannot connect to (local).


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ADDITIONAL INFORMATION:


A network-related or instance-specific error occurred while establishing a connection to SQL Server. 
The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. 
(provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2)

解决办法：

1、在防火墙规则中将sqlservr.exe添加到允许的规则中。确保1433端口可用

2、在SQL Server Configuration Manager 工具中将ip 访问开启，把所有动态端口TCP Dynamic Ports置空，在指定端口中填写你指定的端口如：1433

3、重启实例

参考：http://blogs.msdn.com/b/sqlexpress/archive/2005/05/05/415084.aspx