Migrating Exchange on-premises mailboxes to Office 365
This is the main part of the on-premises Exchange to Office 365 migration series. This part is all about the essential steps of the cut-over migration. Let us start the cut-over migration:
- Verify the on-premises domain in your Office 365 organization –
In cut-over migration, SMTP address of each on-premises mailbox is required to create an email address for the new Office 365 mailbox. For this, your On-premises domain must be verified in Office 365. Follow these steps one-by-one to do this:
- Sign in to Office 365 with administrator credentials.
- Go to Setup>Domains. Click Add Domain to add a new domain.
- Provide the domain name that you use for on-premises Exchange and then click Next.
- Now, on Verify domain page, verify the entered domain either using Sign in to GoDaddy or Add a TXT record; then click Next.
- Follow the instructions of the DNS provider (usually TXT record is needed to verify the ownership by DNS records. You need to wait for about 15 minutes after entering a TXT or MX record).
- In the Office 365 domain wizard, choose done, verify now, and you’ll see a verification page. Choose Finish.
Here, you need to create migration endpoint. This helps in the connection between Exchange on-premises and Office 365 email system. Create it as described below:
- Open Exchange Admin Center in O365. Go to Recipients>Migration. From More…, select Migration endpoints.
- At this opened page, select New +.
- On the Select the migration endpoint type page, choose Outlook Anywhere and click Next.
- Now enter the email address of any user in the on-premises Exchange organization (for testing purposes). Also, provide a username and password of an account that has necessary administrative permissions in the on-premises organization. Click Next.
- After the successful Office 365 connection, the connection settings are displayed. Click Next to continue.
- On the Enter general information page, enter the Migration end-point name. Finally, click New to create the migration endpoint.
To create a cut-over migration batch, perform these steps:
- Open Exchange Admin Center. Go to recipients>migration. Select New +>Migrate to Exchange Online.
- On the Select a migration type page, select Cutover migration and then click Next.
- On the Confirm migration end-point page, confirm the displayed connection settings information about the migration endpoint. Click Next.
- Enter the migration batch name. Click Next.
- Now, select either Automatically start the batch (begins as soon as you click) or Manually start the batch later (status is set to start later) according to your convenience. Finally, click New to create the migration batch.
If you chose the second option, Manually start the batch later, go to Recipients>Migration. On the migration dashboard, select the batch created and then click Start. The status of the migration batch changes to Syncing, i.e., migration is in process.
The synchronization is working if users get created in Office 365 admin center as the migration proceeds. On completion of the migration, the Syncing status is changed to Synced.
Now, you need to point your DNS (MX) records to Office 365. This is to ensure emails are delivered to your Office 365 mailboxes. To change DNS record:
- In Exchange admin center, go to Setup>Domains on the left sidebar.
- Now choose the domain for verification.
- Now, choose Start setup on the Setup page.
- Then click Verify on the Verify domain page.
It will need up to 3 days for the change of DNS records. So, continue to the next after three days only.
After ensuring that MX record is changed and all mailboxes data are migrated, you need to delete the cut-over migration batch.
For deleting the migration batch, open Exchange Admin Center, go to Recipients>Migration. Select your migration batch from the list and then click Delete.
After the completion of migration, you can assign licenses to all Office 365 user accounts. However, this is not all that the user requires to perform. There are certain post-migration processes (explained in 3rd part of the cut-over migration series) which are required in cut-over migration for smooth access of mailboxes data. Read 3rd part of the series to get information about the processes required to be executed after the migration.
Exchange administrators can migrate user mailboxes to Office 365 using cut-over migration. The steps are provided in this article in brief only.