Isolating Connection Problems

When a DB-Library application has problems connecting to SQL Server, there might be a problem with SQL Server, with the network, or with both. Regardless of which network you are running on, there are several items that you can check to help isolate the problem. Check that:

• The local connection to SQL Server over named pipes is available. You can test a local named pipes connection by using isql with no servername argument. If you cannot make a local connection using named pipes, either you are using an invalid login or there is a problem with SQL Server.
• The network components match the requirements specified in Microsoft SQL Server Startup.
• The default client Net-Library is appropriate for your network. You can determine and, if necessary, change the default client Net-Library by running the Client Configuration Utility (for all clients except MS-DOS-based clients). For MS-DOS-based clients, you change the default client Net-Library by loading a different terminate-and-stay-resident (TSR) program in place of DBNMPIPE.EXE, as described in the instructions included in your Net-Library package.
• The network connection information on the server is appropriate for your network (if you are running SQL Server and listening on other interprocess communication [IPC] mechanisms in addition to named pipes). You can determine and, if necessary, change which networks SQL Server is listening on by using the setup program.
• The network connection between the client workstation and the server computer is established. (The procedures for testing network connections for all supported networks are provided in the following sections.) If you test the network connection and determine that it is not open, check that:
  • The hardware connection is not disabled on account of loose connectors or plugs.
  • The network software is installed and running on both computers.