Migrating to Exchange Online Part 3

March 18, 2013 by Dennis Rea in IT Infrastructure, Office365, Technical Documentation

Exchange Cutover Migration Specifics

Email provider Northwind Traders is an Exchange hosted provider. This may be loosely considered as being similar to an on-premises Exchange environment; however, it is unlikely that the provider will give you full control of the environment as they are also hosting other customers. When migrating from an on-premises Exchange environment, you have three migration options: remote move; staged migration; and cutover migration. Because the first two options are not practical with a hosted Exchange provider, you must perform a cutover migration.

When migrating hosted Exchange mailboxes to Office 365 in a cutover Exchange migration:

  • Office 365 provisions new mailboxes in your Office 365 organization. It creates an Office 365 mailbox for each user account in your hosted Exchange organization. Hosted distribution groups and contacts are also migrated to Office 365.
  • After the new Office 365 mailboxes are created, the migration service migrates email messages, contacts, and calendar items from the hosted Exchange mailboxes to the corresponding Office 365 mailboxes.
  • After the initial migration, the hosted Exchange and Office 365 mailboxes are synchronized every 24 hours, so that new email sent to the hosted Exchange mailbox is copied to the corresponding cloud-based mailbox.

When you are ready, you can route email directly to the Office 365 mailboxes, complete the migration, and then remove your hosted Exchange organization.

Ironically, this is the simplest migration to perform and provides the best results. With a cutover migration, users’ mail items, calendars, and contacts are all migrated in a single procedure.

As I inferred above, not all Exchange hosted providers are equal; for example, some do not provide the ability to grant full control to all mailboxes in your organization. You will need to work around any such restrictions.

Additional information on cutover migrations is detailed in the following Microsoft TechNet article; although it deals with migrating from an on-premises Exchange environment, most of the details remain relevant and useful for migrating from a hosted Exchange provider. Migrate All Mailboxes to Exchange Online with a Cutover Migration.

As with other migration types, it is necessary to verify the domain name to Microsoft. Let’s assume that the name of the provider is Northwind Traders, and that our registered domain name is treyresearch.com. Further details for verifying domain names can be found at Verify your domain and change name servers at any DNS hosting provider or domain registrar.

Establish an account that has full control permission on all your hosted mailboxes

To perform a cutover migration, it is critical that one account on your hosted provider has full control access to all mailboxes you want to migrate. Depending on your provider, this may mean assigning permissions to each mailbox one by one. For example, the following provider enables full access by using the procedure below.

The account to which you grant full control permissions is the account that you will use when setting up the cutover migration batch later.

Verify your email domain with Office 365 and configure it as an accepted domain

To create users with your treyresearch.com email addresses, you must specify the domain name; verify that you own that domain name; and then add it as an accepted domain. To do this, perform the following steps:

  1. Log in to Office 365 using the administrator account.
  2. In the Admin portal, under Manage your organization, under domains, click Manage your website and email domains.

  3. Click Add a domain.

  4. Type the name of the domain, and then click next.

  5. In the Tell us about… screen, select Yes to confirm that you already have the email address.

    Note that in this example, I have selected Yes for the website selection. For your organization, you may opt to make another choice. Click Next.

  6. Select Confirm that you own <your company name>.

  7. Click the drop-down list and then select your provider.

    In this example, treyresearch.com uses Go Daddy’s DNS to host their namespace, so we select Go Daddy in the Office 365 dialog box.

  8. You are prompted with a screen instructing you what value to enter in a TXT DNS record. Office 365 provides great instructions here to assist with registering the domain. It is worth printing out the instructions. Click Print to print the instructions provided on the Office 365 site. If you cannot print, it might be necessary to switch between the screens.

    Scroll down and make a note of the value of the TXT record you will need to add to your provider’s DNS; e.g., in my example it was MS=ms87257449.


Add a TXT record to your registrar’s DNS

Perform the following steps to add a TXT record to your registrar’s DNS:

  1. To change the settings in DNS, go to your registrar’s domain management page, in this case Go Daddy.
  2. Open the Go Daddy control panel.
  3. Click Domain Manager.

  4. Click the domain name, and then under DNS Manager, click Launch.

  5. In DNS Manager, click Add Record.

  6. At this point, the Office 365 Help screen dialog boxes will provide you with the record details you need to enter. Keep the printout at hand, or jot down the values. Once you have the record value, in the Add DNS Record dialog box, click the down arrow for the Record type: box, and then choose TXT (Text).

  7. For TXT Name, type or paste the following: @

    For TXT Value, type or paste the value you noted previously; e.g., MS=ms87257449

    For TTL, leave the value set to 1 Hour.

    Click OK.

    Note: While you are editing the DNS records, now is a good time to confirm that the time to live (TTL) of the MX record is no longer than 1 hour. If it is, reduce it to 1 hour, which will make the final transition a lot smoother.

  8. Save the Zone File.
  9. Click OK.


Complete verification of the domain name

Perform the following steps to complete verification of the domain name:

  1. Wait at least 15 minutes for the changes to take effect across the Internet. Come back to the Office 365 portal, and then click done, verify now.

    If the verification of the DNS record cannot be confirmed immediately, wait and try again later. In my experience, these names typically take less than 1 hour to resolve.

  2. Once confirmed, the following screen is displayed. Click next. (In this example, we are only confirming ownership of the domain name.)

  3. Now that you have confirmed that you have ownership of the domain and that it is configured as an accepted domain, you can create email addresses using the domain name. Click Finish.

The next stage is to perform a cutover migration.

Navigation to the migration settings in the Exchange Administration Center

Important: To navigate to the Exchange Administration Center (EAC) in the Office 365 Small Business tenant, it is necessary to manually enter the URL for the EAC into your browser. To do this, perform the following steps:

  1. In the Office 365 portal, at the top of the page, select Outlook.
  2. In Outlook Web App, go to the address bar in your browser and replace the URL to the right of https://outlook.office365.com/ with ecp. For example, if your Outlook Web App URL is https://podxxx.outlook.com/owa/, change it to https://podxxx.outlook.com/ecp and then press Enter. This will take you to the EAC.
  3. When you are finished, return to the Office 365 portal by clicking Admin at the top of the page.

    The EAC will now be displayed.

  4. In the Exchange Administration Center, click migration.

  5. Click new and then select Migrate to Exchange Online.

  6. In the New Migration Batch screen, select Cutover migration and then click next.

  7. In the Email address text box, type the email address of an account that has administrative rights over all mailboxes you want to migrate.
  8. In the Account with privileges text box, type the email address again. (All the hosting providers I’ve migrated from do not provide an account in the format domain\username.)
  9. In the password textbox, type the password for the account.
  10. Click Next.

    Office 365 will now try to communicate with the hosted Exchange provider to verify the Autodiscover connection settings.

    If the test connection isn’t successful, you will be prompted to manually specify the connection settings. If you get an error and the migration endpoint cannot be created, see this video.

    If the test connection to the Exchange server is successful, the Start the Migration
    page is displayed. This is where you create a migration endpoint, and where the settings for your hosted Exchange server and RPC proxy server fields are automatically populated. This migration endpoint is saved and may be used for future migration batches. Click Next.

  11. In the New migration batch name field, type the migration batch name. Choose a name that will make sense to you later if you need to return here. Click next.

  12. Select the name of the mailbox to be sent a report of the migration. You must enter a mailbox name here.
  13. Select Automatically start the batch and then click new.

    You are returned to the Exchange Administrative Center, where you can view a report on the progress of the migration. Clicking the refresh button will update the details.

  14. For more specific details on the migration progress, click View details.


  15. Click the refresh button to see further progress.

  16. Press refresh. The status of each mailbox will show as provisioning à Queued à Synching à Synched (or Failed).
  17. For any mailboxes that fail, examine the right pane for error descriptions. In the migration I performed for the purposes of this article, I forgot to assign the migration account full control permissions on a mailbox and therefore received the error shown below.


When a user’s mailbox is successfully migrated, the hosted Exchange mailbox and Office 365 mailbox are synchronized once every 24 hours until you delete the cutover migration batch. Once all mailboxes are synced, you are ready to complete the migration. Follow these steps:

  1. Configure your MX record to point to Office 365. (Until you change your MX record, email sent to users is still routed to your hosted Exchange provider. When you configure your organization’s MX record to point to Office 365, all email is sent directly to Office 365).
  2. After you change the MX record and verify that all email is being routed to Office 365 mailboxes, wait for 24 hours and refresh the migration batch. Now you are ready to delete the cutover migration batch.

When you delete a cutover migration batch, the migration service cleans up any records related to the migration batch, and deletes the migration batch. The batch is removed from the list of migration batches on the migration dashboard.


Users can now log in and access their mailboxes

Users can now log in. But what login credentials should they use? Open the mailbox you specified when configuring the migration batch, and you will see a mail item for every mailbox created, containing the logon ID and password. Distribute these following your regular security procedures.

Your users can now log in and enjoy the features of the new Office 365.