Depinde cum te conectezi la SQL Server, cu Windows Authentication sau cu SQL Authentication. Citat din http://download.microsoft.com/documents/uk/partner/training/sales/downloads/microsoft-products.ppt :

"SQL Server provides two authentication mechanisms: SQL Server authentication (user names and passwords are stored in and checked by SQL Server) and Windows authentication (user names and passwords are stored in and checked by a Windows service such as Active Directory).

SQL Server authentication does not require a Windows CAL, Windows authentication does."

Răzvan