The Server Network utility allows the network protocols on which SQL Server listens to be enabled or disabled. The Server Network utility also provides a way to configure the properties of each protocol. One of the properties for TCP/IP is the option to hide an instance of SQL Server that is installed on the computer. SQL Server 2000 Books Online contains the following information about hiding an instance of SQL Server:
When you hide an instance of SQL Server, responses to broadcasts from clients attempting to enumerate those instances of SQL Server present on the network are disabled.
To hide an instance of SQL Server:
- Open the SQL Server Network Utility.
- Select the instance that you want to hide. (This is only available on SQL Server 2000 instances).
- Select TCP/IP from the list of enabled protocols.
- Click Properties.
- Select the Hide Server check box.
- Click OK.
If you enable the Hide Server
option and then you restart the computer that is running SQL Server 2000, the server no longer responds to broadcasts from clients that are attempting to locate instances of SQL Server on the network.
An instance of SQL Server 2000 is automatically set to listen on port 2433 and this cannot be modified. If you attempt to reset the port number through the Server Network Utility, the change takes affect and is updated in the registry. However, when you restart the SQL Server 2000 instance, the port number is automatically set back to 2433.
You must disable the Hide Server
option on one of the SQL Server instances to allow the server to listen on TCP/IP.
This behavior is by design.
If you attempt to enable the Hide Server
option on multiple SQL Server 2000 instances that are installed on one computer, only one of the instances is able to listen on TCP/IP. The first instance to come online grabs port 2433. All subsequent instances are not able to obtain port 2433. The following error message is written to the SQL Server error log:
SuperSocket Info: Bind failed on TCP port 2433
If you subsequently disable the Hide Server
option, the port on which SQL Server listens remains at 2433. You must manually make a change to reflect a new TCP port.