Migrating On-Prem Distribution Groups to Exchange Online in Hybrid Mode

Tech_Team_Blues 

######## Global Variables ############
Set-Location -Path $env:USERPROFILE\Documents
#Get-PSSession | Remove-PSSession
$UserCredential = Get-Credential
$ListOfGroupsToMigrate = Import-csv .\GroupMigration.csv
#######################################
$ListOfGroupsToMigrate | ForEach-Object {
$SingleGroupToMigratePSMTP = $_.GroupEmailAddress
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri http://ExhangeServerFQDN.com/PowerShell/ -Authentication Kerberos -Credential $UserCredential
Import-PSSession $Session -Allowclobber
$distrotomovedetails = Get-DistributionGroup -Identity $SingleGroupToMigratePSMTP 
$distrotomovedetails | Export-csv .\singlegroupdetailsbeforedelete.csv -NoTypeInformation
$distrotomovedetails | ForEach-Object{
    $DistributionGroupName = $_.PrimarySmtpAddress
    Get-DistributionGroupMember -Identity $DistributionGroupName | ForEach-Object{
        [PSCustomObject]@{
            DistributionGroup = $DistributionGroupName
            MemberName = $_.DisplayName
            EmailAddress = $_.PrimarySmtpAddress
           #Other recipient properties here
        }
    }
} | Export-csv .\GroupmembersBeforeDel.csv -NoTypeInformation

#########################################
$groupowner = $distrotomovedetails.ManagedBy
$GroupOwnerCorrected = $groupowner.split('/')[-1]
$GroupOwnerCorrected.ToString()
$Managedby = Get-ADuser -Filter "displayName -eq '$GroupOwnerCorrected'"
$distrotomovedetails | fl

# Extract All Email Addresses for single group one per line so you can easily add back in EXO
$addresses = @()
    Foreach ($mbx in $distrotomovedetails) {
    Foreach ($address in $mbx.EmailAddresses) {
    $obj = "" | Select-Object Identity,Alias,EmailAddress,RecipientType
    $obj.Alias = $mbx.Alias
    $obj.Identity = $mbx.Identity
    $obj.RecipientType = $mbx.RecipientType
    $obj.EmailAddress = $address.ToString().SubString(0)
    $addresses += $obj 
        } } $addresses | Export-Csv .\SingleDistroGroupsmtpaddresses.csv -NoTypeInformation
$addresses
#Remove OnPremises Group
Remove-DistributionGroup -Identity $distrotomovedetails.Identity -Confirm:$false -Verbose
Start-Sleep 120

#Create On-Premises Contact
$ExternalEmailAddress = $distrotomovedetails.Alias + "@tenant.mail.onmicrosoft.com"
New-MailContact -DisplayName $distrotomovedetails.DisplayName -Alias $distrotomovedetails.Alias -ExternalEmailAddress $ExternalEmailAddress -OrganizationalUnit "OU=Contacts,OU=Exchange Accounts,DC=lge-mdr,DC=com"
Set-MailContact -Identity $distrotomovedetails.PrimarySmtpAddress -HiddenFromAddressListsEnabled $true

#Close Session with OnPremise Exchange
Get-PSSession | Remove-PSSession -Verbose

#Connect EXO
Import-Module ExchangeOnlineManagement
Connect-ExchangeOnline -Credential $UserCredential
Write-Host -ForgroundColor Cyan "Running AAD Connect Sync"
#Remotely Run AAD Connect Delta Sync
$session = New-PSSession -ComputerName FQDNAADServer.com
Invoke-Command -Session $session -ScriptBlock {Import-Module -Name 'ADSync'}
Invoke-Command -Session $session -ScriptBlock {Start-ADSyncSyncCycle -PolicyType Delta}
Remove-PSSession $session
#Pause until AAD Connect Sync can run and Azure AD to catch up
Write-Host -ForgroundColor Green "Pausing for AAD Connect to run and then we check EXO for the group"
function Start-Sleep($seconds) {
    $doneDT = (Get-Date).AddSeconds($seconds)
    while($doneDT -gt (Get-Date)) {
        $secondsLeft = $doneDT.Subtract((Get-Date)).TotalSeconds
        $percent = ($seconds - $secondsLeft) / $seconds * 100
        Write-Progress -Activity "Sleeping" -Status "Sleeping..." -SecondsRemaining $secondsLeft -PercentComplete $percent
        [System.Threading.Thread]::Sleep(500)
    }
    Write-Progress -Activity "Sleeping" -Status "Sleeping..." -SecondsRemaining 0 -Completed
}

Start-Sleep 200
Write-host -ForegroundColor Cyan "Verifing the group  is gone from Azure AD, command will proceed once group is not showing in EXO" $distrotomovedetails.PrimarySmtpAddress
while($GetDistroFinder -ne $null){
Write-Host -ForegroundColor Cyan "Checking EXO for the old synced Distro Group"
$GetDistroFinder = Get-DistributionGroup -Identity $distrotomovedetails.PrimarySmtpAddress
Start-Sleep 10
}
Write-Host -ForegroundColor Green "Group Appears to have been removed please verify on Azure AD"
Read-Host -Prompt "Hit Enter To Proceed"

############ Recreate Group in the cloud ###########################################################################################################################################
Write-Host -ForegroundColor Cyan "Recreating the group in EXO"
#Create the EXO Distro group
New-DistributionGroup -DisplayName $distrotomovedetails.DisplayName -Alias $distrotomovedetails.Alias -Name $distrotomovedetails.Name -MemberDepartRestriction $distrotomovedetails.MemberDepartRestriction -MemberJoinRestriction $distrotomovedetails.MemberJoinRestriction -PrimarySmtpAddress $distrotomovedetails.PrimarySmtpAddress -RequireSenderAuthenticationEnabled:$false -ManagedBy $Managedby.UserPrincipalName -Verbose

#Add additional SMTP and x500 addresses to the group.
Write-Host -ForegroundColor Green "Adding SMTP and x500 Addresses Back to" $distroprimarysmtp
$EmailAddressesToAdd = Import-Csv .\SingleDistroGroupsmtpaddresses.csv
$EmailAddressesToAdd | ForEach-Object {
$AliasOfGroup = $_.Alias
$AddressToAdd = $_.EmailAddress
$x500 = "x500:"+ $distrotomovedetails.LegacyExchangeDN
$GroupLookup = Get-DistributionGroup -Identity $AliasOfGroup
Set-DistributionGroup -Identity $GroupLookup.Identity -EmailAddresses @{Add=$AddressToAdd} -Verbose
}

#Add Group Members Back to Group
Write-Host -ForegroundColor Magenta "Adding Members Back to Group"
$GroupMembers = Import-Csv .\GroupmembersBeforeDel.csv
$GroupMembers | ForEach-Object {
$Distroprimarysmtp = $_.DistributionGroup
$MemberPrimarySMTP = $_.EmailAddress
Write-Host "Adding $memberprimarysmtp to $Distroprimarysmtp"
Add-DistributionGroupMember -Identity $Distroprimarysmtp -Member $MemberPrimarySMTP
}

#Confirm Group
Get-DistributionGroup $distroprimarysmtp | Select Alias,PrimarySmtpAddress,ManagedBy,IsDirsynced,WhenCreated | FT
}

Thank you for sharing this script Gregory Hall. I'm pretty much new to this as well.
In line with BrentPirolli's questions, please from where should this be run, Exchange on-prem or EXO? I shall also appreciate if you can please point out any customizations that need to be done to the script before running it in a new environment.

Gregory HallThis is pretty incredible! thanks for sharing. For a relative rookie at this, what of your script needs customized for my environment? I see a line referencing:

http://ExhangeServerFQDN.com/PowerShell/

which I'm guessing needs my URL... and

"@tenant.mail.onmicrosoft.com"

which I'm guessing I need to fill in with my tenant name in place of "tenant"... correct? Are there other areas?

Also... seeing this kicks off referencing:

$ListOfGroupsToMigrate = Import-csv .\GroupMigration.csv

Is there a specific script/format you are using to get that GroupMigration.csv or are you just pulling from something like:

$groups = get-adgroup -filter { (GroupCategory -eq 'Distribution') } -properties mail, name

$groupscsv = "C:\logs\GroupMigration.csv"

$groups | export-csv -Path $groupscsv

Hello TonyRedmond,

Sorry, your answer is quite old now but I have a question regarding the situation.

I'm in a similar situation with the customer here:

- Made a hybrid deployment to migrate from Exchange 2010 to Office 365;

- Have AAD Connect (and ADFS)

- Migrated almost all users (and shared mailboxes, etc.)

- The end goal is to shut down the Ex10 server since I've told uninstalling it is a terrible idea. We'll be managing things like SMTP Addresses from the AD Attribute Editor.

Now about the DGs: We've sync'ed them all with AADC. We can see them in o365 AC and ExO but not manage them as expected.

If I would like to manage them there, can I simply remove the DG OU from AADC Sync?

EDIT: Thinking about it, I've realized doing what I've described above should change the ID of the DG since it isn't a migrated object but a created one. Therefore, I suppose people who use Autocomplete (meaning everybody ^^) will be screwed.

Users will have to get the DG from the Online GAL, correct?

Thanks in advance for your answer

Can you please elaborate more on, "how to export DL (on-premises) and then create in Cloud using PowerShell"? 

Thanks!