Troubleshooting of SQL Server nonexistent or access denied

1. Question proposal

A set of C/S invoicing systems normally used by an enterprise. A new client is connected to the database Server (SQL Server 2000 is installed) when a fault occurs, the system prompts "[DBNETLIB] [ConnectionOpen (connect ().] SQL Server does not exist or access is denied. The system cannot log on, and other clients work normally. 2. troubleshooting process and ideas for such fault prompts. Generally, the solution to this fault is to check the firewall and port 1433 settings on the client. The faulty client is installed with the Kaspersky 6.0 Internet security package. After adding port 1433 to Kaspersky's "Network Settings, the fault prompt is changed to "general network error (recv ()", which causes many reasons for this fault prompt information and is difficult to determine. For this reason, the SQL SERVER Client settings of the clients that are working normally and the clients that have faults are found to use the "Named pipes" protocol with priority, use the name of the server to connect to the database server. If a faulty client uses the "TCP/IP" protocol as the priority and uses the ip address of the server to connect to the database server, the default port is 1433, set "Named pipes" to a priority-enabled protocol on the faulty client. If you use the server name to connect to the database server, the connection is normal and runs properly. The fault is related to the TCP/IP protocol. Run the netstat-an command on the SERVER (Windows 2000 Server SP4 + SQL SERVER 2000, with the IP address 10.140.90.249). The result is as follows: from the above content, we can see that the TCP/IP protocol on the Server does not enable listening to port 1433. Search for information about SQL Server and port 1433 on the Internet, it is found that port 7.0 is enabled by default for SQL Server 1433, and port 2000 is disabled by default before SP4. Ask the Administrator to install the SP4 patch for SQL Server 1433 on the Server, because the SQL Server 2000 version is not displayed in "about", go to "query analyzer" and check the SQL Server 2000 version. In "query analyzer", run: the return value of SELECT @ VERSION is "8.00.194 RTM", which is the original value of SQL Server 2000. First version, further ask the Administrator to learn that the SQL Server service on the Server was not stopped when SP4 was installed, SQL Server 2000 SP4 explicitly requires that the SQL Server service and all client programs on the Server be stopped before installation. Therefore, it is determined that SQL Server 2000 SP4 on the Server is not successfully installed. The relationship between SQL Server 2000 and version can be found online. After you reinstall SQL Server 2000 SP4 on the Server, the following message is displayed: "A suspended file has been created during the previous installation of the program. You must restart the computer before running the program ." This indicates that the previous SP4 was not successfully installed and the server was restarted. The prompt continues. Start the Registry Editor and go to the HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Control \ Session Manager branch to delete the PendingFileRenameOperations project, then, SQL Server 2000 SP4 is successfully re-installed. Then execute the netstat-an command on the server. port 1433 is in the "LISTENING" State, set the faulty client to the TCP/IP connection mode, and start the program, the connection is successfully completed, and the error message is no longer displayed. 3. The current software system is becoming more and more complex and involves more and more systems. troubleshooting cannot be confused by the surface of the fault. It is necessary to analyze and eliminate the fault gradually, go to forums and official websites on software systems to learn about related products, especially patch information, so that you can get twice the result with half the effort and avoid detours. This kind of fault also occurs in the standalone status. Generally, the SQL server Client sets TCP/IP as the priority-enabled protocol and uses the IP address to connect to SQL SERVER, when there is a problem with the physical connection of the network cable or the IP address settings.