Office 365 Migrations

	Cut over	Staged	Hybrid	IMAP
Exchange Versions	2003 and later	2003 / 2007	2010 / 2013	2000 Onward
Pros	Simple	Greater than 2000 users	More time (no down time)	Migrate legacy mailboxes
Cons	Max 2000 Users	Coexistence	Requires Hybrid Exchange Wizard	Only Inbox Migrated
Cons	Max 2000 Users	Coexistence	Requires Hybrid Exchange Wizard

Cut over Migration

A cut over migration is a “all at once” method of migrating.

Prerequisites

Outlook anywhere (HTTP over RPC) AKA Auto discover

SSL Certificates

Custom domain added to Office 365 tenant account

Preparing the Cut over Migration

If Outlook anywhere / auto discover is already configured, skip to step 7.

1. Create a Custom certificate request

Template: (No Template) Legacy Key
PKCS #10
Certificate Name: Outlook Anywhere
Common name: CN=domain.com
Enter an Alternative DNS: autodiscover.domain.com and mail.domain.com
Extended Key Language: Server Authentication
Key Type: Exchange
Key Size: 2048
Make Key Exportable
Save CSR as Base64.

2. Submit the CSR to a public CA. Once it’s received, import the certificate

3. Export the certificate

Export Private key: yes

PKCS #12

Save the certificate to the exchange server

4. Check firewall for required ports

HTTPS: 443

5. Create DNS Records (CNAMEs)

mail.domain.com
autodiscover.domain.com

6. Import the Certificate into Exchange

Open IIS
Locate the OWA Site
Assign the certificate to the https bindings.

7. Test exchange connectivity

https://testconnectivity.microsoft.com/

Executing the Migration

1. Ensure the on-premises account has correct permissions

2. Add the domain to Office 365

Only step 1 is required for this process there is no need to add licences yet as there are no accounts in Office 365 to assign them to.

3. On the on-Premises exchange, go to Migration

Select cut over migration
Enter credentials of the administrator
Enter the exchange server: exchange.ADDomain.local
Enter the RPC Proxy: mail.domain.com
Name the Migration Batch: Batch 1

The batch will then run.

4. Change the MX Records to point to Office 365

5. Disable Synchronization and delete batch on the local exchange

6. Decommission Server

Guide to continue…

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