Example - Migrate Exchange 2003 To Office 365
Posted by Mandeep Singh, Last modified by Mandeep Singh on 12 August 2017 11:05 PM
How to migrate Exchange 2003 to Office 365 using the built in migration tool
Get DNS Login
Request Login and verify DNS zone file access so you can update External DNS when needed.
Get Domain Admin Login to Exchange and DirSync Servers
Get client to provide you with domain admin login and have them spin up a separate DirSync VM for you to use to connect AD to Office 365. Attach it to the domain as a member server and run all Windows updates. Then Install Remote Administration Features Via Server Manager for AD Users and Computers and DNS
Two Weeks Before Migration
Two weeks before the migration begins verify again you have Domain admin remote access to the two servers you need.
Two Weeks Before Migration - Clean Up AD
Login to the client Domain Controller and go through all the subset of users that will be migrated to Office 365. Verify the Exchange Advanced tab for the user has the simple display name as the email user. i.e.=[email protected] the display name is the bit before @.
Install DirSync and Connect It To Office 365
Setup Cloudns.com Account (Optional)
As a precaution against DNS record issues I have the end user setup a free cloudns.com account and populate that with the domain(s) and the proper dns entries for all the services, switching the ones to do with Office 365 to what they should be after the migration. I have this staged incase something goes wonky with the current DNS provider I can just switch Name Servers at the Registrar and get mail flowing.
Merge Mailboxes At This Time
If you want to merge any mailboxes like support or info then you should do this now on the existing Exchange server before you migrate to the cloud. Adjust your CSV dump as needed to remove the mailboxes you merged leaving only the one you want.
Export AD Users To CSV
Use the following command to dump the existing AD users email list to a CSV. Then send this over to the client and have them delete the ones that do not need mailboxes or licenses assigned to them on Office 365. Open CMD on the exchange 2003 server.
csvde -m -f AD-Email-Dump.csv -r "(&(objectClass=user)(mail=*))" -l "displayname,mail"
Clean up CSV dump
Open the CSV file in Excel and delete the columns for DN and Displayname leaving only the mail column with the email addresses. Rename the email column to EmailAddresses
Save this CSV as an Excel Sheet with the prefix OriginalDump-companyusers.xlsx and send it to your contact at the client and have them delete all the emails that are not going to be migrated to Office 365
Take this clean list and cleanout all the white spaces by sorting, then save the file as CSV with a new file name prefix CleanList-companyusers.csv
Save this list as it will be needed twice during the migration.
Setup Migration Batch
Login to the office 365 portal with the admin account and navigate to Exchange, Recipients then Migration.
Once the endpoint is set then you can proceed to setup the Migration batch using the CSV dump you created earlier.
Back on the main Exchange, Recipients then Migration screen hit the Plus sign to create the new migration batch.
Go through the CSV and assign the needed Licenses on the Office 365 portal for Exchange and what ever other services you subscribed to.
Start on a Friday as early as possible doing about 45 -50 users each batch and let it run; keeping an eye on the sync via the office 365 portal. This will take a day or two depending on the size of the mailboxes and speed of the internet upload at the site.
Convert AD Exchange 2003 Users
Once the migration batch is completed you can then proceed to update AD properties removing the Exchange 2003 and replacing it with the Office 365 pointers.
Convert Users - Download Scripts
Export Migrated Users AD Info From Office 365
Update Users In AD With Downloaded AD Info From O365
Create a new folder
Download the files Unzip the one and change the file extension of the other to ps1 as per the instructions on the download page
Convert Users - Office 365 Powershell
Login to the DirSync server and open Powershell (run as administrator)
#Store Office 365 Admin Creds
#Connect to Office 365
#Import the session commands
#Set Execution Policy Unsigned so you can run the scripts
Convert Users - Export Migrated User Settings From Office 365
Once connected to Office 365 via the powershell steps above then you will need to run the ExportO365UserInfo.ps1 script and dump that to CSV for use in the next step.
# Once this is run you should see a cloud.csv file in the c:\scripts folder on the DirSync Server where you ran this powershell script.
Convert Users - Import User Settings Into AD - Mail Enable Users
copy the whole scripts folder over to the old Exchange 2003 server then remote into the old Exchange 2003 server to run the vbs script.
Change DNS Settings
After the Migration batch has finished you then need to change both internal and external DNS for the switch over to Office 365 mail.
On both the external and internal DNS zone file you need to delete any A or Cname records with the following prefixes
Add The Following Cname Records
Delete Old MX Records and Add the one for Office 365
Add TXT Record
Add SRV Records For Exchange Autodiscover and Lync
Delete The Migration Batch
Login to the office 365 portal and delete the migration batch to finalize the migration
Repair Outlook Profiles
Most Exchange 2003 Outlook users will have the old server name hard coded into the account and in order for the autodiscover to work you need to go into the account properties and hit the option for repair outlook profile.