SQL Server database security

SQL Server operates in one of two security (authentication) modes: Windows authentication mode Windows authentication mode allows a user to connect through a Windows user account. Mixed mode Mixed mode allows users to connect to an instance of SQL Server using either Windows authentication or SQL Server authentication. Users who connect through a Windows user account can use trusted connections in either Windows authentication mode or mixed mode. Siemens Digital Industries Software recommends using mixed mode authentication, where the user is required to input a database user logon ID and password to be able to connect to the SQL Server.