Authentication in SQL Server Analysis Services
Authentication is the process of verifying the identity of a user or application attempting to connect to SQL Server Analysis Services (SSAS). SSAS supports various authentication methods to ensure secure access to your multidimensional or tabular models.
Supported Authentication Methods
SSAS primarily relies on Windows authentication and SQL Server authentication. The choice of method often depends on your network environment and security requirements.
1. Windows Authentication
Windows authentication is the most common and recommended method for connecting to SSAS when it's running on a Windows domain. It leverages the existing security infrastructure of Windows.
- Integrated Security: When using Windows authentication, the client application uses the credentials of the logged-in Windows user to authenticate with SSAS. This eliminates the need for users to enter separate credentials for SSAS.
- Service Accounts: The SSAS service itself typically runs under a dedicated service account. This account must have appropriate permissions to access data sources and other resources required for SSAS operations.
- Domain and Workgroup: SSAS can authenticate users from the local machine, a trusted domain, or even multiple domains.
2. SQL Server Authentication
SQL Server authentication allows users to connect to SSAS using a specific SSAS login and password, separate from Windows credentials. This method is useful in scenarios where Windows authentication is not feasible or desired.
- SSAS Logins: You create and manage SSAS-specific logins within the SSAS instance.
- Password Management: Passwords must be managed carefully for these logins.
- Mixed Mode: SSAS can be configured to support both Windows and SQL Server authentication simultaneously.
Connecting with Different Authentication Methods
When establishing a connection to SSAS, you'll typically specify the authentication method and credentials in your connection string or through the client application's connection dialog.
Connection String Examples
Windows Authentication (Integrated Security):
Provider=MSOLAP.8;Data Source=YourServerName;Initial Catalog=YourDatabaseName;Integrated Security=SSPI;Impersonation Level=Impersonate;
SQL Server Authentication:
Provider=MSOLAP.8;Data Source=YourServerName;Initial Catalog=YourDatabaseName;User ID=YourSSASLogin;Password=YourSSASPassword;
Authentication vs. Authorization
It's important to distinguish between authentication and authorization:
- Authentication: Verifies *who* you are.
- Authorization: Determines *what* you are allowed to do (e.g., access specific databases, cubes, or perform certain operations).
After a user is successfully authenticated, SSAS applies authorization rules to control their access to resources.
Best Practices
- Prefer Windows Authentication for enhanced security and simplified user management.
- Use dedicated, least-privilege service accounts for the SSAS service.
- Regularly review and update SSAS logins and permissions.
- Implement robust password policies if using SQL Server Authentication.
- Utilize SSAS roles and Windows groups for effective authorization management.