Isolating Connection Problems

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

• For servers running Microsoft Windows NT, the local connection to SQL Server over Named Pipes is available. You can test a local Named Pipes connection by using osql 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.

  For servers running Microsoft Windows 95 or Windows 98 operating systems, the local connection to SQL Server uses the Shared Memory Net-Library.

• The network components match the requirements specified in SQL Server Books Online.
• The default client Net-Library is appropriate for your network. You can determine and, if necessary, change the default client Net-Library by using SQL Server Client Network Utility in the Microsoft SQL Server program group.
• 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 using SQL Server Network Utility in the Microsoft SQL Server program group.
• The network connection between the client workstation and the server 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 due to loose connectors or plugs.
  • The network software is installed and running on both the client workstation and the server.