mssql连接出错：了解错误53的原因（mssql 错误53）

The Microsoft SQL Server error 53 is a commonly encountered error when attempting to establish a connection to a Microsoft SQL Server Database. The error is prompted when a specific SQL instance is not running, when the incorrect server name is used to identify the server, or when certain Windows authentication components are not enabled. It can also occur when attempting to connect to a different domain. If you encounter this error and cannot get a satisfactory response from your database server, it’s important to understand the underlying causes.

The error 53 usually appears in one of the following formats:

“Cannot connect to [server name]. Error 53: The network path was not found”

“A network-related or instance-specific error occured while establishing a connection to the SQL Server. Server is not found or not accessible. Check if instance name is correct and server is no available”

Most commonly, the error 53 is caused by a missing registry value or an incorrectly defined registry value. The registry value is responsible for identifying the instance of SQL Server and the individual involved. When these values are incorrect, the error 53 appears.

It is possible to manually check the registry values to determine the cause of the issue; however, you should exercise caution and make sure you have a backup of your registry first. To check the registry value, open the Registry Editor and navigate to the following location:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\SQLEXPRESS

Look for the ServerName key and verify that it matches the name of your server instance. If the value is incorrect or missing, replace or add it, and try connecting to the server again.

The second, more common cause of the error 53 is Windows Firewall. To ensure that your connection to the SQL Server is allowed through the firewall, you will need to enable the appropriate port. First, you need to determine which port your SQL Server is using. Consult your server logs, or if your server is running default configuration settings, it is likely to be port 1433. Then, enable the port by going to the Control Panel and navigating to the Windows Firewall application. Add a new inbound rule for the port and specify the port range and select the correct protocol.

If the errors persist, it’s possible that the authentication components of Windows are not configured correctly. If so, you can attempt to resolve the issue by enabling the Windows authentication mode of Windows. This can be done in the SQL Server Configuration Manager. Select ‘Security’, and in the Authentication Mode box select the ‘Windows Authentication Mode’ option.

If you are still having trouble connecting to your server, the final step is to contact your server administrator and ask them to investigate the cause of the issue. They may need to check server configurations or firewall settings, or they may request that you use a different instance name or port.

In summary, when attempting to connect to a Microsoft SQL Server Database, the error 53 appears when a specific SQL instance is not running, when the incorrect server name is used, when Windows authentication components are not enabled, or when attempting to connect to a different domain. The most common causes of this problem are missing registry keys, ports being disabled in the firewall, and Windows authentication components. Fortunately, these issues can be rectified by manually checking registry values, enabling the necessary ports in the firewall, and enabling Windows authentication in the SQL Server Configuration Manager.