【正文】 being used by the instance of SQL Server. 大連交通大學(xué) 2020屆本科生畢業(yè)設(shè)計(jì)（論文）外文翻譯 2 For additional information about SQL Server munication ponents and NetLibraries, see the following topics in SQL Server Books Online: ? Communication Components ? Client and Server NetLibraries ? Managing Clients Troubleshoot connectivity issues Most of the connectivity issues that you may notice in SQL Server 2020 occur because of problems with TCP/IP, Windows authentication, or a bination of TCP/IP and Windows authentication. Important Before you start to troubleshoot connectivity issues in SQL Server 2020, make sure that the MSSQLServer service is started on the puter that is running SQL Server. Verify your DNS settings The name resolution process in Domain Name System (DNS) is used to resolve the IP address to the name of the instance of SQL Server. If the name resolution process does not work correctly, the instance of SQL Server is not reachable, and you may receive one or more of the following error messages: SQL Server does not exist or access denied General Network Error Cannot Generate SSPI Context To verify that the name resolution process is resolving the correct server, you can ping the server by using the server name and the IP address of the server. To do so, follow these steps: 1. Click Start, and then click Run. 2. In the Run dialog box, type cmd in the Open box, and then click OK. 3. At the mand prompt, run the following mand: ping Server Name Note the IP address that is returned. 4. At the mand prompt, run the following mand (where IP address is the IP address that you noted in step 3): ping –a IP address 大連交通大學(xué) 2020屆本科生畢業(yè)設(shè)計(jì)（論文）外文翻譯 3 Verify that the mand resolves to the correct server name. If either of the specified mands are not successful, time out, or do not return the correct values, the DNS lookup is not working correctly or the problem occurs because of other working or routing issues. To see your current DNS settings, run the following mand at a mand prompt: ipconfig /all To work around this problem, add an entry for the server to the %systemroot%\system32\drivers\etc\hosts file on the client puter. You can also work around the problem by connecting to the server by using the Named Pipes Netlibrary. Verify the enabled protocols and aliases Connectivity problems may occur if the alias on the client puter is set incorrectly. You can view the aliases by using Client Network Utility. To do so, follow these steps: 1. Start Client Network Utility. If the SQL Server client tools are installed on the puter that is running the client application, follow these steps to start Client Network Utility: a. Click Start, and then point to Programs. b. Point to Microsoft SQL Server, and then click Client Network Utility. If the SQL Server client tools are not installed on the client puter, follow these steps to start Client Network Utility: a. Click Start, and then click Run. b. In the Run dialog box, type cliconfg in the Open box, and then click OK. 2. In the SQL Server Client Network Utility window, click the General tab, and then enable all the protocols that you want to use. Note You must at least enable the TCP/IP protocol and the named pipes protocol. 3. Click the Alias tab, and then verify the aliases that are configured for the instance of SQL Server. 4. Verify the properties of the aliases to make sure that the server name or IP address and the protocol are configured correctly. You can create a new alias to test the connectivity by using the server name, the IP address, or even by using a different protocol. Note Earlier versions of Microsoft Data Access Components (MDAC) have a different user interface for Client Network Utility. Therefore, if you do not see the 大連交通大學(xué) 2020屆本科生畢業(yè)設(shè)計(jì)（論文）外文翻譯 4 options that are listed in this article, install a later version of MDAC on the puter that is running the client application. Verify that the instance of SQL Server is listening correctly To verify that the instance of SQL Server is listening on named pipes, TCP/IP, or another protocol that you are using at the client application, open the current SQL Server error log file. The SQL Server error log file may contain entries that are similar to the following: 20201106 09:49: server SQL server listening on TCP, Shared Memory, Named Pipes. 20201106 09:49: server SQL server listening on :1433, :1433. If you analyze the entries in the SQL Server error log file, you can verify that the instance of SQL Server is listening on the correct IP address and on the correct port. By default, a default instance of SQL Server listens on the port 1433. You can also use Server Network Utility to verify the protocol settings for SQL Server and to change the properties in SQL Server, including the protocols that can connect to SQL Server and the ports that can be used. For more information about using Server Network Utility, see the SQL Server Network Utility topic in SQL Server Books Online. Sometimes, SQL Server 2020 may not bind to port 1433 or any other specified port. This problem may occur if the port is being used by another application or if you are trying to connect by using an IP address that is not correct. Therefore, the TCP/IP connections to SQL Server may not be successful and you may receive the following error message in the SQL Server error log file: 20201114 15:49: server SuperSocket Info: Bind failed on TCP port 1433. If you cannot connect to the instance of SQL Server by using a TCP/IP connection, try to use the named pipes protocol or the Shared Memory protocol. Run the following mand at a mand prompt to obtain information about the ports that are in use: NETSTAT –an You can also use the Portqry mandline utility to obtain more information about the ports that are in use. No