Connecting to Named Microsoft SQL Server Instances

    Originally published on 07-21-2011 09:50 AM


    One feature of the Microsoft SQL Server relational database management system is the ability to install multiple named instances on the same host computer. When you take this approach, you give each instance a unique name. You can then use either dynamic or static TCP/IP port assignments. In order to get full advantage from the multiple named instances, you must also install and run the SQL Server Browser Service on the same computer on which the multiple database instances are installed.

    Whether the browser service is installed and running affects how you refer to each instance when configuring an expressor Database Connection.

    • If the browser service is running, you reference both the computer and instance names when specifying the Host connection value. For example, if the host computer is named MYSERVER and the database instance is named SQLEXPRESS, you would enter MYSERVER\SQLEXPRESS for the Host connection value and leave the Port connection value empty.
    • If the browser service is not running, you reference only the computer name when specifying the Host connection value and enter the TCP/IP port number used by this database instance into the Port connection value.
      • If the database instances are using static TCP/IP port number assignments, you most likely already know the port number assigned to each instance.
      • If the database instances are using dynamically assigned TCP/IP port numbers, you must obtain the current port assignment. This information is available from the SQL Server Configuration Manager; open the Properties window for the TCP/IP protocol of the desired instance and note the value assigned to the TCP Dynamic Ports entry in the IPAll grouping.