Problem: During the MDT deployment process, information can be retrieved from Microsoft SQL Server® databases. However, errors might be generated that relate to an improperly configured firewall on the database server.
Possible Solution: The Windows Firewall in Windows Server 2008 helps prevent unauthorized access to computer resources. However, if the firewall is configured incorrectly, attempts to connect to a SQL Server instance may be blocked. To access an instance of SQL Server that is behind the firewall, configure the firewall on the computer that is running SQL Server. For more information on configuring firewall ports for SQL Server, see the Microsoft Support article How do I open the firewall port for SQL Server on Windows Server 2008?