Uses Windows Authentication to validate attempted connections. If the sa password is blank when the security mode is being changed, the user is prompted to enter an sa password.
Windows Authentication is much more secure than SQL Server Authentication. When possible, you should use Windows Authentication.
SQL Server and Windows Authentication mode
Uses mixed mode authentication to verify attempted connections, for backward compatibility with earlier versions of SQL Server. If the sa password is blank when the security mode is being changed, the user is prompted to enter an sa password.
Changing the security configuration requires a restart of the service. When changing the Server Authentication to SQL Server and Windows Authentication mode the SA account is not automatically enabled. To use the SA account, execute ALTER LOGIN with the ENABLE option.
Enables an account for use by xp_cmdshell. Proxy accounts allow for the impersonation of logins, server roles, and database roles when an operating system command is being executed.
The login used by the server proxy account should have the least privileges required to perform the intended work. Excessive privileges for the proxy account could be used by a malicious user to compromise your system security.
Audits all attempts to access statements and objects and records them to a file in the \MSSQL\Data directory for default instances of SQL Server, or the \MSSQL$instancename\Data directory for named instances of SQL Server. For more information, see c2 audit mode Option.