Office 365 migration with same domain

Reason for moving the Office 365 tenants with same domain:

1. You may need to change the Office 365 providers like Godaddy, Rackspace, Comcast to directly move it to Microsoft.
2. To avoid the latency of emails you wish to change your Office 365 servers from Germany to the USA or from China to the USA or vice versa.
3. Companies may prefer to switch to a different Office 365 tenant while keeping the domain name the same during business acquisitions and mergers. 
4. Performing Microsoft O365 migration with the same domain name means that users can continue to use their existing email addresses, which reduces the risk of confusion or disruption to business operations.
5. By keeping the same domain name, companies can maintain their branding and reputation with their customers, suppliers, and partners, as the email addresses and website URLs will remain the same.
6. Changing domain names can also result in email delivery issues, as emails may be marked as spam or blocked by email servers due to the change in domain name. By keeping the same domain name, companies can avoid these issues.

Steps involved before migrating Office 365 in the same domain:

• Step 1: Move the users of source Office 365 to another domain
  • Go to the Microsoft 365 admin center

    

  • Select ‘Users’ > ‘Active users’.

    

  • Select the boxes next to the names of all the users you want to move.

    

  • Select ‘More options (…)’, at the top of the page, and then choose ‘Change domains’.

    

  • In the Change domains pane, select a different domain like xxx.onmicrosoft.com

  You'll need to do this for yourself too, if you're on the domain that you want to remove. When you edit the domain for your account, you'll have to log out and login back in using the new domain you chose to continue.

• Step 2: Remove the domain from source Office 365 server

  • In the admin center, go to ‘Settings’ > ‘Domains page’

    

  • On the Domains page, select the domain that you want to remove

    

  • In the toolbar pane, select ‘Remove domain’

    

  • Follow any additional prompts, and then select Close

  Note: It can take as little as 5 minutes for Office 365 to remove a domain if it's not referenced in a lot of places such as security groups, distribution lists, users, and Office 365 groups. If there are many references that use the domain it can take several hours (a day) for the domain to be removed.

  After the domain removal is complete, users will not be able to access their email, unless they know their tenant name and log in with their tenantname.onmicrosoft.com email addresses.

• Step 3: Admin account creation on source for migration
  • In the Office 365 admin portal, change the UPN of the admin account to the onmicrosoft.com address.
  • Create an administrator account (Global admin) in Office 365 to be used for migration.
  • Test the mailbox and email access by logging into the tenant

  Note: Test the access to the tenantname.onmicrosoft.com addresses, not to the domainname.com addresses. Make sure that the tenantname.onmicrosoft.com account is attached to each mailbox in Office 365. By default, it should be attached.

• Step 4: Verify the domain on destination Office 365 server
  • Verify the domain in the Destination Office 365 account. We recommend the use of the wizard in Office 365 for this operation, because after the domain is verified with the Text record, it offers to change all the users to the new Default Domain.

  Note: Since the domain was previously added to the account, all that needs to be done is to click the Verify button. If the domain is unable to be verified, and there is an error saying the domain already exists on another account, contact Microsoft and inform them that the domain needs to be manually deprovisioned.

  • Create an administrator account in Office 365 to be used for migration
  • Set up accounts on Office 365 and assign licenses. These can be created in several ways:
    • Manually create the mailboxes, one at a time.
    • By bulk import, via CSV file. Import the CSV file and create the mailboxes.
    • By DirSync, AAD Sync or AAD connect.
  • Confirm that every user has the Destination ‘domain.com’ domain name added to their mailbox. Add manually if necessary.
  • Prepare the tenant to send and receive large mail items in Office 365.
• Step 5: Update your DNS records

  MX Record update: On the DNS provider's portal, change the primary MX record to reflect the DNS settings for the new Office 365 organization. The DNS settings to change include Autodiscover, MX, and SPF records. Also, remove the old settings.

  These settings can be found in the Office 365 admin portal,

  • Inside Office 365, click Admin in the header.
  • On the Admin page, click Domains in the left pane.
  • Click the domain name to be set up, and then click DNS Settings. 
  • This page lists the DNS records necessary to set in order to use the Office 365 services. Steps to add DNS records to connect to your domain.
• Step 6: Migrate your Source Office 365 to the target Office 365

  Finally, migrate mailboxes from one tenant to another with EdbMails migration tool.