ADO.NET Provider for Microsoft Exchange

Build 22.0.8462

Establishing a Connection

Available Schemas

There are two services available for connecting to Exchange. These are EWS (Exchange Web Services) and the Microsoft Graph. Exchange Web Services is available for both Exchange OnPremise and Online, but is no longer receiving updates. Microsoft recommends switching to using the Microsoft Graph for Exchange Online users. Both are available with our tool.

To switch between the two, use the Schema connection property to set either EWS or MSGraph. If you wish to use EWS with Exchange Online, set Schema to EWS and the Platform to Exchange_Online.

Connecting to Microsoft Exchange using Exchange OnPremise

When using an OnPremise edition of Exchange, OnPremise Set User, Password, and AuthScheme; by default, the provider performs Basic authentication, but Windows (NTLM), Kerberos, and delegated authentication are also supported.

Kerberos

Please see Using Kerberos for details on how to authenticate with Kerberos

In addition to the authentication values, set the Server property to the address of the Exchange server you are connecting to and set Platform to the Microsoft Exchange version. Finally, set Schema to EWS.

Connecting to Microsoft Exchange using Exchange Online

When connecting to Exchange Online, authentication will be done via OAuth. If you are connecting to Exchange Online platform through EWS, set the AuthScheme property to either AzureAD, AzureServicePrincipal or AzureMSI. Otherwise if you will be using Microsoft Graph to connect to Exchange Online, resources will be pulled from a different service so the Schema should be set to MSGraph. When Schema is set to MSGraph, the Platform value will be ignored.

Azure AD

Azure AD is a connection type that leverages OAuth to authenticate. OAuth requires the authenticating user to interact with Microsoft Exchange using an internet browser. The provider facilitates this in several ways as described below. Set your AuthScheme to AzureAD. The rest of the AzureAD flows assume that you have done so.

Desktop Applications

CData provides an embedded OAuth application that simplifies OAuth desktop Authentication. Alternatively, you can create a custom OAuth application. See Creating a Custom AzureAD App for information about creating custom applications and reasons for doing so.

For authentication, the only difference between the two methods is that you must set two additional connection properties when using custom OAuth applications.

After setting the following connection properties, you are ready to connect:

  • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
  • OAuthClientId: (custom applications only) Set this to the client Id in your application settings.
  • OAuthClientSecret: (custom applications only) Set this to the client secret in your application settings.
  • CallbackURL: Set this to the Redirect URL in your application settings.

When you connect the provider opens the OAuth endpoint in your default browser. Log in and grant permissions to the application. The provider then completes the OAuth process:

  1. Extracts the access token from the callback URL and authenticates requests.
  2. Obtains a new access token when the old one expires.
  3. Saves OAuth values in OAuthSettingsLocation that persist across connections.

Web Applications

When connecting via a Web application, you need to register a custom OAuth app with Microsoft Exchange. See Creating a Custom AzureAD App. You can then use the provider to get and manage the OAuth token values. Get an OAuth Access Token

Set one of the following connection properties groups depending on the authentication type to obtain the OAuthAccessToken:

  1. Client Secret
    • OAuthClientId: Set this to the client Id in your app settings.
    • OAuthClientSecret: Set this to the client secret in your app settings.
  2. Certificate
    • OAuthClientId: Set this to the client Id in your app settings.
    • OAuthJWTCert: Set this to the JWT Certificate store.
    • OAuthJWTCertType: Set this to the type of the certificate store specified by OAuthJWTCert.

You can then call stored procedures to complete the OAuth exchange:

  1. Call the GetOAuthAuthorizationURL stored procedure. Set the AuthMode input to WEB and set the CallbackURL input to the Redirect URI you specified in your app settings. If necessary, set the Permissions parameter to request custom permissions.

    The stored procedure returns the URL to the OAuth endpoint.

  2. Open the URL, log in, and authorize the application. You are redirected back to the callback URL.
  3. Call the GetOAuthAccessToken stored procedure. Set the AuthMode input to WEB. Set the Verifier input to the "code" parameter in the query string of the callback URL. If necessary, set the Permissions parameter to request custom permissions.

To connect to data, set the OAuthAccessToken connection property to the access token returned by the stored procedure. When the access token expires after ExpiresIn seconds, call GetOAuthAccessToken again to obtain a new access token.

Headless Machines

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

  1. Choose one of these two options:

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

  2. Then configure the provider to automatically refresh the access token from the headless machine.

Option 1: Obtain and Exchange a Verifier Code

To obtain a verifier code, you must authenticate at the OAuth authorization URL.

Follow the steps below to authenticate from the machine with an internet browser and obtain the OAuthVerifier connection property.

  1. Choose one of these options:

    • If you are using the Embedded OAuth Application click Microsoft Exchange OAuth endpoint to open the endpoint in your browser.
    • If you are using a custom OAuth application, create the Authorization URL by setting the following properties:
      • InitiateOAuth: Set to OFF.
      • OAuthClientId: Set to the client Id assigned when you registered your application.
      • OAuthClientSecret: Set to the client secret assigned when you registered your application.
      Then call the GetOAuthAuthorizationURL stored procedure with the appropriate CallbackURL. Open the URL returned by the stored procedure in a browser.

  2. Log in and grant permissions to the provider. You are then redirected to the callback URL, which contains the verifier code.
  3. Save the value of the verifier code. Later you will set this in the OAuthVerifier connection property.
Next, you need to exchange the OAuth verifier code for OAuth refresh and access tokens. Set the following properties:

On the headless machine, set the following connection properties to obtain the OAuth authentication values:

  • InitiateOAuth: Set this to REFRESH.
  • OAuthVerifier: Set this to the verifier code.
  • OAuthClientId: (custom applications only) Set this to the client Id in your custom OAuth application settings.
  • OAuthClientSecret: (custom applications only) Set this to the client secret in the custom OAuth application settings.
  • OAuthSettingsLocation: Set this to the path to the file where the driver saves the OAuth token values that persist across connections.

After the OAuth settings file is generated, you need to re-set the following properties to connect:

  • InitiateOAuth: Set this to REFRESH.
  • OAuthClientId: (custom applications only) Set this to the client Id assigned when you registered your application.
  • OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
  • OAuthSettingsLocation: Set this to the file containing the encrypted OAuth authentication values. Make sure this file grants read and write permissions to the provider to enable the automatic refreshing of the access token.

Option 2: Transfer OAuth Settings

Prior to connecting on a headless machine, you need to create and install a connection with the driver on a device that supports an internet browser. Set the connection properties as described in "Desktop Applications" above.

After completing the instructions in "Desktop Applications", the resulting authentication values are encrypted and written to the path 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.

On the headless machine, set the following connection properties to connect to data:

  • InitiateOAuth: Set this to REFRESH.
  • OAuthClientId: (custom applications only) Set this to the client Id assigned when you registered your application.
  • OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
  • OAuthSettingsLocation: Set this to the path to your OAuth settings file. Make sure this file gives read and write permissions to the provider to enable the automatic refreshing of the access token.

Admin Consent

Admin consent refers to when the Admin for an Azure Active Directory tenant grants permissions to an application which requires an admin to consent to the use case. The embedded app within the CData ADO.NET Provider for Microsoft Exchange, contains no permissions that require admin consent. Therefore, this information applies only to custom applications.

Admin Consent Permissions

When creating a new OAuth app in the Azure Portal, you must specify which permissions the app will require. Some permissions may be marked stating "Admin Consent Required". For example, all Groups permissions require Admin Consent. If your app requires admin consent, there are a couple of ways this can be done.

The easiest way to grant admin consent is to just have an admin log into portal.azure.com and navigate to the app you have created in App Registrations. Under API Permissions, there will be a button for Grant Consent. You can consent here for your app to have permissions on the tenant it was created under.

If your organization has multiple tenants or the app needs to be granted permissions for other tenants outside your organization, the GetAdminConsentURL may be used to generate the Admin Authorization url. Unlike the GetOAuthAuthorizationURL, there will be no important information returned from this endpoint. If the grants access, it will simply return a boolean indicating that permissions were granted.

Once an admin grants consent, authentication may be performed as normal.

Client Credentials

Client credentials refers to a flow in OAuth where there is no direct user authentication taking place. Instead, credentials are created for just the app itself. All tasks taken by the app are done without a default user context. This makes the authentication flow a bit different from standard.

Client OAuth Flow

All permissions related to the client oauth flow require admin consent. This means the app embedded with the CData ADO.NET Provider for Microsoft Exchange cannot be used in the client oauth flow. You must create your own OAuth app in order to use client credentials. See Creating a Custom AzureAD App for more details.

In your App Registration in portal.azure.com, navigate to API Permissions and select the Microsoft Graph permissions. There are two distinct sets of permissions - Delegated and Application permissions. The permissions used during client credential authentication are under Application Permissions. Select the applicable permissions you require for your integration.

You are ready to connect after setting one of the below connection properties groups depending on the authentication type.

  1. Client Secret
    • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
    • AzureTenant: Set this to the tenant you wish to connect to.
    • OAuthGrantType: Set this to CLIENT.
    • OAuthClientId: Set this to the client Id in your app settings.
    • OAuthClientSecret: Set this to the client secret in your app settings.
  2. Certificate
    • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
    • AzureTenant: Set this to the tenant you wish to connect to.
    • OAuthGrantType: Set this to CLIENT.
    • OAuthClientId: Set this to the client Id in your app settings.
    • OAuthJWTCert: Set this to the JWT Certificate store.
    • OAuthJWTCertType: Set this to the type of the certificate store specified by OAuthJWTCert.

Authentication with client credentials takes place automatically like any other connection, except there is no window opened prompting the user. Because there is no user context, there is no need for a browser popup. Connections will take place and be handled internally.

Azure Service Principal

Azure Service Principal is a connection type that goes through OAuth. Set your AuthScheme to AzureServicePrincipal. The authentication as an Azure Service Principal is handled via the OAuth Client Credentials flow, and it does not involve direct user authentication. Instead, credentials are created for just the app itself. All tasks taken by the app are done without a default user context, but based on the assigned roles. The application access to the resources is controlled through the assigned roles' permissions.

Note: You must create a custom application prior to assigning a role. See Creating a Custom AzureAD App for more information.

When authenticating using an Azure Service Principal, you must register an application with an Azure AD tenant. Follow the steps below to create a new service principal that can be used with the role-based access control.

Assign a role to the application

To access resources in your subscription, you must assign a role to the application.

  1. Open the Subscriptions page by searching and selecting the Subscriptions service from the search bar.
  2. Select the particular subscription to assign the application to.
  3. Open the Access control (IAM) and select Add > Add role assignment to open the Add role assignment page.
  4. Select Owner as the role to assign to your created Azure AD app.

Complete the Authentication

You are ready to connect after setting one of the below connection properties groups, depending on the configured app authentication (client secret or certificate).

In both methods

Before choosing client secret or certicate authentication, follow these steps then continue to the relevant section below:

  1. AuthScheme: Set this to the AzureServicePrincipal in your app settings.
  2. InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
  3. AzureTenant: Set this to the tenant you wish to connect to.
  4. OAuthClientId: Set this to the client Id in your app settings.
Authenticating using a Client Secret

Continue with the following:

  1. OAuthClientId: Set this to the client Id in your app settings.
  2. OAuthClientSecret: Set this to the client secret in your app settings.

Authenticating using a Certificate

Continue with the following:

  1. OAuthJWTCert: Set this to the JWT Certificate store.
  2. OAuthJWTCertType: Set this to the type of the certificate store specified by OAuthJWTCert.

MSI

If you are running Microsoft Exchange on an Azure VM, you can leverage Managed Service Identity (MSI) credentials to connect:

  • AuthScheme: Set this to AzureMSI.

The MSI credentials are automatically obtained for authentication.

Copyright (c) 2023 CData Software, Inc. - All rights reserved.
Build 22.0.8462