【正文】 receive the following error message in the SQL Server error log file: 20200807 20:46: server Error: 17832, Severity: 20, State: 6 20200807 20:46: server Connection opened but invalid login packet(s) sent. Connection closed. For additional information, click the following article numbers to view the articles in the Microsoft Knowledge Base: 154628 INF: SQL logs 17832 with multiple TCP\IP connection requests 328476 TCP/IP settings for SQL Server drivers when pooling is disabled Note You may not notice the stress on TCP/IP sockets if you are running SQL Server 2020 SP3 or SQL Server 2020 SP3a because a limit on the number of login packets was added. The 17832 error occurs when you use thirdparty drivers to connect to the 大連交通大學(xué) 2020屆本科生畢業(yè)設(shè)計（論文）外文翻譯 8 instance of SQL Server. To resolve this problem, contact the thirdparty vendor and obtain drivers that have been tested to work with SQL Server 2020 SP3 and SQL Server 2020 SP3a. See if the instance of SQL Server is started in singleuser mode If the instance of SQL Server that you are trying to connect to is started in singleuser mode, only one connection can be established with SQL Server. If you have software running on your puter that automatically connects to SQL Server, the software can easily use the only connection. For example, the following software can automatically connect to the instance of SQL Server: ? SQL Server Agent ? Thirdparty backup software ? Thirdparty monitoring software ? Thirdparty virus software ? Microsoft Inter Information Services (IIS) ? SQL Server Enterprise Manager The client application that is trying to connect to the instance of SQL Server receives the following error message: SQL Server does not exist or Access Denied This error generally occurs during SQL Cluster Setup and service pack setup when the setup process starts the instance of SQL Server in singleuser mode. The specified applications may automatically connect to the instance of SQL Server using the only available connection, and setup is not successful. To determine if the instance of SQL Server has been started in singleuser mode, check to see if the SQL Server error log file has an entry that is similar to following: 20200731 11:26: spid3 Warning ****************** 20200731 11:26: spid3 SQL Server started in single user mode. Updates allowed to system catalogs. Verify named pipes connectivity to SQL Server If you cannot connect to the instance of SQL Server by using named pipes, make sure that the instance of SQL Server is configured to accept named pipes connections. Troubleshoot connections that time out during the recovery process Every time that you start an instance of SQL Server, SQL Server recovers each database. During this recovery process, SQL Server rolls back the transactions that are 大連交通大學(xué) 2020屆本科生畢業(yè)設(shè)計（論文）外文翻譯 9 not mitted. SQL Server also rolls forward the transactions that are mitted and the changes that were not written to the hard disk when the instance of SQL Server was stopped. When the recovery process is plete, SQL Server logs the following message in the SQL Server error log file: Recovery Complete During the recovery process, SQL Server may not accept connections. Clients that try to connect to the instance of SQL Server during that time may receive an error message that is similar to the following: Timeout Expired The SQL Server Agent service may not start because it waits for SQL Server to recover the databases. Therefore, when you receive the following message in the SQL Server error log file, the connections will no longer fail with a timeout error: Recovery Complete If the recovery process takes a long time, you may have to additionally troubleshoot the recovery process. Test different ways to connect to the instance of SQL Server If you experience connectivity problems when you connect to the instance of SQL Server, you can use one or more of the following methods to work around the connectivity problem. ? Test the connectivity to the instance of SQL Server by using both SQL Server Authentication and Windows authentication. ? Test the connectivity to the instance of SQL Server from other data sources, such as an ODBC DSN, a .udl file, SQL Query Analyzer, SQL Server Enterprise Manager, the isql utility, or the osql utility. ? Test the connectivity to the instance of SQL Server by using different protocols. You can specify different protocols by creating a new alias for the instance of SQL Server using that protocol. You can also specify the protocol in your connection string by adding tcp:, np:, lpc:, or rpc: to the beginning of the name of the instance of SQL Server. For example, if TCP/IP connections are not successful, named pipes connections succeed. ? Test the connectivity by using a different login account to help you determine if the problem is associated with a particular login account. 大連交通大學(xué) 2020屆本科生畢業(yè)設(shè)計（論文）外文翻譯 10 ? Try to add an entry that corresponds to the IP address of the puter that is running the instance of SQL Server to the %systemroot%\system32\drivers\etc\hosts file. ? Try to connect to the instance of SQL Server from the puter that is running SQL Server and from the client. ? If you are connecting from the puter that is running SQL Server, you can specify . or (local) (without the quotation marks) instead of the server name and then connect. ? Try to connect to the instance of SQL Server by using the IP address instead of the server name. ? Try to specify the specific port that the instance of SQL Server is listening on, either by creating an alias or by adding a port number to the connection string (MyServer\MyInstance, 1433, for example). Capture work monitor traces If the connectivity problem is not resolved by the steps that are mentioned in Test different ways to