Migrating Mailboxes From On-Premise to Office 365

KB ID 0001419

Problem

This post continues from Part-One where we connected both our domain, and on-premise 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.

Office365 Admin

Add a domain.

Office365 Add a domain

Enter your public domain name > Next.

Office365 Add your domain

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.

Office365 Add your domain TXT Record

As below, once created click (Verify).

Office365 domain DNS TXT Record Settings

Ill manage my own DNS records > Next.

Office365 domain DNS TXT Record Settings

We are only concerned with Exchange > Next.

Office365 Manage DNS Settings

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-premise, and you want your Autodiscover to point there. I leave everything pointing to my on-premise server!

Office365 Manage Exchange DNS Settings

So I DON’T create the records (below) unless I’m about to decommission an on-premise Exchange server.

Setup Office 365 Exchange DNS Records

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-premise server of you may start getting mail blocked.

i.e.

Microsoft Suggests: “v=spf1 mx include:servers.mcsv.net ?all”

Use: “v=spf1 ip4:123.123.123.123 mx include:servers.mcsv.net ?all”

Finish.

Office 365 Exchange DNS Setup

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-premise Exchange organisation as it did before!

Test Email Flow

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.

Allocate O365 Licence

Then from the Office365 Admin Center > Recipients > Migration > Add > Migrate to Exchange Online > Remote move migration > Next.

Migrate Mailbox to Office 365

Add in your ‘Test user’ > Next.

Add User to O365 Migration Batch

Supply your Exchange administrative credentials > Next.

Administrator Credentials Mailbox Migraiton

Put in your MRS proxy FQDN > Next

MRS Proxy Office 365 Endpoint

Note: You may see the following error

MRS Proxy Error ‘The connection to the server could not be completed’

Give the batch a name > Next.

Office 365 Migration Batch

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.

Start Office 365 Migration Batch

You can view a ‘hight level’ progress, or click the download link;

Office 365 Migration View Progress

To view a more detailed report.

Office 365 Migration Progress Report

Note: You can connect to O365 PowerShell online, and view the migrations from command line like we normally do with an on-premise mailbox migration. See the following link;

Connect to Office 365 Exchange PowerShell

When finished complete the migration.

Office 365 Mailbox Migration Completion

Migration completed.

Office 365 Mailbox Migration Completed

Viewing the same thing from PowerShell;

Office 365 Mailbox Migration Progress

Now test mallow in/out from on-premise and from Office365, then make sure mail also flows between on-premise and Office 365 (both ways).

Check Mail flow From On Premise to O365

Make sure calendar sharing scheduling also works between on-premise and Office 365 mailboxes.

Check Free Busy Calendaring

Once you are happy, you can migrate the rest of the mailboxes.

 

Related Articles, References, Credits, or External Links

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Author: PeteLong

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