BUG: SQL Server May Not Listen on TCP/IP Sockets When TCP/IP is the Only Protocol

In a SQL Server 2000 custom installation, if TCP/IP is the only selected protocol and all other protocols are disabled, SQL Server may not initialize and listen on TCP/IP sockets. The Server Network Utility shows that it is listening only on TCP/IP port 1433 even though it is not. Clients may fail to connect and the following error messages may occur: Note that the preceding error message can exist for TCP/IP connectivity problems other than this specific situation. To identify if SQL Server is not listening on TCP/IP, check to see if the value for TcpPort in the following registry key is incorrectly set to blank or empty:

To work around this problem, follow these steps:

1. Start Registry Editor (Regedt32.exe).
2. Locate the TcpPort value in the following key in the registry:
   Named instance:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\[InstanceName]\MSSQLServer\SuperSocketNetLib\Tcp\TcpPort
   
   Default instance:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\MSSQLServer\SuperSocketNetLib\TCP\TcpPort
3. On the Edit menu, click String. Enter either of the following values:
   1. Type the port number you want. -or-
      
      
   2. Enter a value of 0 to have SQL Server dynamically detect and assign a port the next time SQL Server starts.
4. Click OK.
5. Quit Registry Editor.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.