SQL Server – Authentication Mode – Windows Mode and Mixed Mode

SQL Server – Authentication Mode

During the installation of SQL Server you can choose the authentication mode for Database Instance. SQL Server support the two authentication mode as

Windows authentication mode:

Windows Authentication mode enables Windows Authentication and disables SQL Server Authentication.  Even if you choose Windows Authentication mode during SQL Server installation “sa” user is created but disable for SQL Server Authentication. But later we you can use “sa” user by enabling for SQL Server Authentication .Any window user can configure as system administrator for the SQL Server Instance.

Mixed authentication mode

Mixed mode enables both Windows Authentication and SQL Server Authentication. If we choose the mixed mode authentication then we have to provide the strong password for the “sa” user.

Note:

• Windows Authentication is always available and cannot be disabled.
• “sa” is  built-in SQL Server system administrator user.