Windows Authentication Mode

Windows Authentication mode leverages Active Directory user accounts or groups when granting access to SQL Server. This is the default and recommended authentication mode, and it allows IT professionals to grant domain users access to the database server without creating and managing a separate SQL Server account. In addition, when using Windows Authentication mode, user accounts are subject to enterprise-wide policies enforced in the Active Directory domain such as complex passwords, password history, account lockouts, minimum password length, and maximum password length.