This section describes how to edit the DSN configuration and then authenticate and connect to Microsoft Exchange APIs.

DSN Configuration

You can use the Microsoft ODBC Data Source Administrator to edit the DSN configuration. Note that the installation process creates a both a user DSN and a system DSN, as described in Installing the Connector.

Note: The connector stores connection information in the Windows registry. To ensure that the connector can write to the registry, either run Power BI as an administrator or use a User DSN for your connection instead of a System DSN.

User DSN

Complete the following steps to edit the DSN configuration:

1. Select Start > Search, and enter ODBC Data Sources in the Search box.
2. Choose the version of the ODBC Administrator that corresponds to the bitness of your Power BI Desktop installation (32-bit or 64-bit).
3. Select the system data source and click Configure.
4. Edit the information on the Connection tab and click OK.

System DSN

Configure the system DSN the same way as the user DSN, except you will need to switch to the System DSN tab before performing Step 3.

If you're using Power BI's On-Premises Data Gateway with Standard mode, you must use the system DSN.

You must also specify a valid location for OAuthSettingsLocation (a path where OAuth credentials are locally stored to avoid repeated OAuth prompts).

This is because the Standard mode runs on service mode and can only access permitted locations, such as C:\Windows\ServiceProfiles\PBIEgwService\AppData\Local\Microsoft\On-premises data gateway.

Connecting to Microsoft Exchange

There are two schemas available for connecting to Exchange:

• Exchange Web Services (EWS), which is no longer being updated but is still available for both Exchange OnPremise and Exchange Online.
  Note: Microsoft recommends that Exchange Online users switch to Microsoft Graph.
• Microsoft Graph

For a look at the data model for each of these schemas, see "Data Model".

To switch between EWS and Microsoft Graph, set Schema to either EWS or MSGraph.

Exchange Online users who still want to use EWS should set Schema to EWS and the Platform to Exchange_Online.

Authenticating to Microsoft Exchange OnPremises

Microsoft Exchange OnPremises supports Basic (default), Digest, Negotiate, or NTLM authentication.

Basic (default)

Microsoft Exchange OnPremises defaults sets Basic as the default authentication. To support Basic authentication, set these properties:

• AuthScheme: Basic.
• User: The user's login ID.
• Password: The user's login password.

Digest

To support HTTP Digest authentication in an On-Premises deployment, set these properties:

• AuthScheme: Digest.
• User: The user's login ID.
• Password: The user's login password.

Negotiate

Negotiate is used to direct the driver to negotiate an authentication mechanism with the server. The purpose of this authscheme is to facilitate Kerberos authentication in an On-Premises deployment. To support Kerberos authentication in an On-Premises deployment, set these properties:

• AuthScheme: Negotiate.
• User: The user's login ID.
• Password: The user's login password.

NTLM

To use Windows NT LAN Manager (NTLM) authentication in an On-Premises deployment, set these parameters:

• AuthScheme: NTLM.
• User: The user's login Id.
• Password: The user's login password.

Authenticating to Microsoft Exchange Online

Microsoft Exchange Online supports several types of OAuth-based authentication.

If you are connecting to Exchange Online platform through EWS, set AuthScheme to AzureAD, AzureServicePrincipal, or AzureMSI.

If you connect to Exchange Online through Microsoft Graph, set Schema to MSGraph. When Schema is set to MSGraph, the Platform is ignored.

Azure AD

Azure AD is Microsoft’s multi-tenant, cloud-based directory and identity management service. It is user-based authentication that requires that you set AuthScheme to AzureAD.

Authentication to Azure AD over a Web application always requires the creation of a custom OAuth application. For details, see Creating an Azure AD Application.

Desktop Applications

CData provides an embedded OAuth application that simplifies connection to Azure AD from a Desktop application.

You can also authenticate from a desktop application using a custom OAuth application. (For further information, see Creating an Azure AD Application.) To authenticate via Azure AD, set these parameters:

• AuthScheme: AzureAD.

• Custom applications only:

  • OAuthClientId: The client Id assigned when you registered your custom OAuth application.
  • OAuthClientSecret: The client secret assigned when you registered your custom OAuth application.
  • CallbackURL: The redirect URI you defined when you registered your custom OAuth application.

When you connect, the connector opens Microsoft Exchange's OAuth endpoint in your default browser. Log in and grant permissions to the application.

The connector completes the OAuth process, obtaining an access token from Microsoft Exchange and using it to request data. The OAuth values are saved in the path specified in OAuthSettingsLocation. These values persist across connections.

When the access token expires, the connector refreshes it automatically.

Headless Machines

To configure the driver with a user account on a headless machine, you must authenticate on another device that has an internet browser.

You can do this in either of the following ways:

• Obtain the OAuthVerifier value as described below in Option 1: Obtain and Exchange a Verifier Code.
• Install the connector on another machine as described below in Option 2: Transfer OAuth Settings. After you authenticate via the usual browser-based flow, transfer the OAuth authentication values.

Option 1: Obtain and Exchange a Verifier Code

1. Find the authorization endpoint.

   Custom applications only: Set these properties to create the Authorization URL:

   • OAuthClientId: The client Id assigned when you registered your application.
   • OAuthClientSecret: The client secret assigned when you registered your application.

   Custom and embedded applications: Call the GetOAuthAuthorizationURL stored procedure.

   1. Open the URL returned by the stored procedure in a browser.
   2. Log in and grant permissions to the connector. You are redirected to the callback URL, which contains the verifier code.
   3. Save the value of the verifier code. You will use this later to set the OAuthVerifier connection property.

2. Exchange the OAuth verifier code for OAuth refresh and access tokens.

   At the headless machine, set these properties:

   • AuthScheme: AzureAD.
   • OAuthVerifier: The verifier code.
   • OAuthSettingsLocation: The location of the file that holds the OAuth token values that persist across connections.

   • Custom applications only:

     • OAuthClientId: The client Id in your custom OAuth application settings.
     • OAuthClientSecret: The client secret in the custom OAuth application settings.

3. After the OAuth settings file is generated, reset the following properties to connect:

   • OAuthSettingsLocation: The location containing the encrypted OAuth authentication values. Make sure this location grants read and write permissions to the connector to enable the automatic refreshing of the access token.

   • Custom applications only:

     • OAuthClientId: The client Id assigned when you registered your application.
     • OAuthClientSecret: The client secret assigned when you registered your application.

Option 2: Transfer OAuth Settings

Before you can connect via a headless machine, you must create and install a connection with the driver on a device that supports an internet browser. Set the connection properties as described above, in Desktop Applications.

After you complete the instructions in Desktop Applications, the resulting authentication values are encrypted and written to the location specified by OAuthSettingsLocation. The default filename is OAuthSettings.txt.

Once you have successfully tested the connection, copy the OAuth settings file to your headless machine.

At the headless machine, set these properties:

• AuthScheme: AzureAD.
• OAuthSettingsLocation: The location of your OAuth settings file. Make sure this location gives read and write permissions to the connector to enable the automatic refreshing of the access token.

• Custom applications only:

  • OAuthClientId: The client Id assigned when you registered your application.
  • OAuthClientSecret: The client secret assigned when you registered your application.

Azure Service Principal

Azure Service Principal is role-based application-based authentication. This means that authentication is done per application, rather than per user. All tasks taken on by the application are executed without a default user context, but based on the assigned roles. The application access to the resources is controlled through the assigned roles' permissions.

For information about how to set up Azure Service Principal authentication, see Creating an Azure AD Application with Service Principal.

Managed Service Identity (MSI)

If you are running Microsoft Exchange on an Azure VM and want to leverage MSI to connect, set AuthScheme to AzureMSI.

User-Managed Identities

To obtain a token for a managed identity, use the OAuthClientId property to specify the managed identity's "client_id".

When your VM has multiple user-assigned managed identities, you must also specify OAuthClientId.