KB ID 0001419
This post continues from Part-One where we connected both our domain, and on-premises Exchange server to Office 365. Now we will add our public domain, and migrate our mailboxes.
Step 3 Adding Domains to Office 365
Before proceeding you will need administrative access to your public DNS records so you can create new records.
Log into Office 365 > Admin Console.
Add a domain.
Enter your public domain name > Next.
Now you need to create a ‘Text Record” in you public domain, the TTL does not really matter but the TXT value must match exactly.
As below, once created click (Verify).
Ill manage my own DNS records > Next.
We are only concerned with Exchange > Next.
STOP: These are the DNS records you need to create if you want everything to point to Office 365, DO NOT CREATE THEM if you want your mail to still get routed to your on-premises, and you want your Autodiscover to point there. I leave everything pointing to my on-premises server!
So I DON’T create the records (below) unless I’m about to decommission an on-premises Exchange server.
If you DID want all mail and auto discover to route to Office 365 that’s fine BUT change the SPF record that Microsoft gives you to include the public IP of your on-premises server of you may start getting mail blocked.
Microsoft Suggests: “v=spf1 mx include:servers.mcsv.net ?all”
Use: “v=spf1 ip4:184.108.40.206 mx include:servers.mcsv.net ?all”
Test Mail Flow
If you have made any public DNS changes, then before you do anything else, make sure mail continues to flow in and out of your on-premises Exchange organisation as it did before!
Step 4 Mailbox Migration
Log into Office 365 and locate a user to perform a test migration on, then allocate them an office 365 licence.
Then from the Office365 Admin Center > Recipients > Migration > Add > Migrate to Exchange Online > Remote move migration > Next.
Add in your ‘Test user’ > Next.
Supply your Exchange administrative credentials > Next.
Put in your MRS proxy FQDN > Next
Note: You may see the following error
Give the batch a name > Next.
Select an email address to be sent a migration report, Note: For the test migration I’m leaving it on ‘Manual Complete’ once Im happy I would select ‘Automatically Complete’ > New.
You can view a ‘hight level’ progress, or click the download link;
To view a more detailed report.
Note: You can connect to O365 PowerShell online, and view the migrations from command line like we normally do with an on-premises mailbox migration. See the following link;
When finished complete the migration.
Viewing the same thing from PowerShell;
Now test mallow in/out from on-premises and from Office365, then make sure mail also flows between on-premises and Office 365 (both ways).
Make sure calendar sharing scheduling also works between on-premises and Office 365 mailboxes.
Once you are happy, you can migrate the rest of the mailboxes.
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