This section explains how to add a Microsoft 365 tenant and configure a domain rewrite project using On Demand Migration. During project setup an Office 365 Global Administrator account is initially required to add each tenant to the project.

How to add a Microsoft 365 tenant

Follow these steps to add each Microsoft 365 tenant for On Demand Migration. If there is an existing tenant from another project, it can be reused. 

1. Log in to On Demand

2. Navigate to Tenants

3. Choose the Add Tenant button

4. Select Commerical Tenant, and choose Add Commerical or GCC Tenant and choose OK.

5. Log in to Office 365 with a Global Administrator account for the source tenant.

6. Accept the requested Application Permissions

7. Choose Finish

8. Repeat steps 2 – 8 for the target tenant

Setting up the Domain Rewrite Project

Follow these steps to setup the Domain Rewrite Project.

1. Log in to On Demand

2. Navigate to Migration

3. Select an existing migration project

4. Click on Domain Rewrite from the Project Dashboard

   

5. Once the On Demand Migration Domain Rewrite module is loaded, click on the Domain Rewrite icon in the main dash view.

   

6. Click the New Project button and bring up the project setup wizard

7. Provide a name and description for the project and click Next

8. Click on the New button to create a new environment or choose any existing environments from the list. Click Next once you have at least two environments selected.

   

   Important Tip: When adding a new environment, On Demand will automatically detect if the tenant is Hybrid or Cloud Only.  Hybrid Environments require additional configuration for each local Active Directory attached to the tenant.

9. If one or more of the environments you selected is connected to an On-Premises Active Directory, the below screen will appear. If you select the No- All Objects are Mailbox Enabled option, you will not be directed to download Directory Sync Agents. Click Next to proceed.

   

10. Choose the source and target environments from the dropdown menu and click Next.

    

11. Configure the domain mapping for your project and click Next.

    

    Important Tip: Domain Mapping will be used to match objects and allows On Demand Migration Domain Rewrite to add the source domain to all matched target objects.

12. Configure the attributes to use to match users and groups. Once complete, click Next

    

    Important Tip: Multiple attributes can be selected and On Demand Migration will evaluate each one until it finds a matching source and target object.  If more than one attribute is selected, the first attribute that matches is used.

13. If there are Hybrid Environments, download the Directory Sync agent and copy the Registration URL and Registration Keys for each environment. These will be used during the agent installation and configuration. This screen will not appear if you previously selected the "No- All Objects are Mailbox Enabled" option.

    

14. Select Domain Rewrite Express Setup or Domain Rewrite Advanced Setup to continue with Domain Rewrite project configuration. Click Next to proceed.

    

     

15. Now we need to configure the DKIM signature for your domain. If you previosly selected the Domain Rewrite Express Setup option, the DKIM setup steps are skipped.

    

16. Copy the DNS record into a notepad and create a TXT record for your domain.  For the purpose of this guide we will create the TXT record for each domain in Azure DNS Zone.

• Demo2.mcslab.qsftdemo.com

  

• Demo3.mcslab.qsftdemo.com

  

   

16. On Demand Migration Domain Rewrite will validate the TXT record and update the DNS Publish Status.  After the TXT Records are published, Click on Next to continue.

    

    Important Tip: Each participating Accepted SMTP Domain from the source and target tenants will require to enable DKIM at the tenant level, additional information can be found at this Microsoft Link How to use DKIM for email in your custom domain - Office 365 | Microsoft Learn

17. Upload a SSL Certificate for each environment.  On Demand Migration will ensure mail delivered during a domain rewrite is always encrypted, secure and private by using this SSL Certificate.  Click Next once the certificates are uploaded.

    

    Important Tip: A single subject certificate with both private and public key must be used.

     

18. Review the project configuration settings and click Next

19. Enter an email address and click on Start Discovery to finish the project setup

Validating Object Matches

This section provides a step-by-step guide on how to validate object matching.

1. Log in to On Demand

2. Navigate to Migration, select the project and click on Domain Rewrite.

3. Select the Domain Rewrite project previously configured.

4. From the Domain Rewrite Project dashboard, verify the Users, Groups and Domain Matching information:

   

5. Click on the total users link to see all Users, then click on Filter and select the Matched checkbox.

   

6. Validate that the users are correctly matched, as shown below.

   

If the Domain Rewrite project is unable to automatically match the users by attributes, you can upload a user list to be used as a mapping file. This process will only update the users found in the file and will not impact any other users in your project.

Uploading a CSV for User Matching

1. Click Update to open the CSV upload wizard.

   

2. Click Download Example List.

   

3. Use this example file to build your mapping list.

   1. Populate the Source UPN and Target UPN columns with the desired mappings.

   2. You can leave the Wave column blank.

   3. The mapping list can contain a maximum of 1000 lines. You can create multiple mapping files and rerun the wizard to upload additional mappings.

   4. After building your list, save as a CSV file.

4. Click Select File.

   

5. Locate the CSV file and click Next.

6. If there are errors within the file, click Fix Errors Now to review the errors.

   1. Download the CSV file of users with errors.

   2. Examine the file and fix any errors found.

   3. Re-upload the modified file.

   4. If errors are still found, you can repeat this process as necessary.

   5. You can also click Proceed As Is to ignore the accounts with errors and map the remaining users.

      

      

7. If there are no errors within the file, the upload is complete.

8. Validate that the users are correctly matched.