I recently assisted a client of ours with implementing Identity Federation (single SignOn) with ADFS. This client was an original BPOS customer that was transitioned to Office 365. The client originally migrated to BPOS from on-premises Exchange 2003. Once we implemented Identity Federation all of the accounts became Federated users and now making any changes to email aliases. This has not been an issue for any of my previous Office 365 deployment as I have always setup the migration in a Hybrid Deployment with an Exchange 2010 SP2 server on-premises. With the Hybrid server, and configuring DirSync with the Hybrid Config checkmark, the email addresses for the users are replicated back to on-prem and can be modified with the EMC or directly via the ProxyAddresses attribute using ADSIEDIT or Attribute Editor in AD Users and Computers (assuming 2008 R2 DCs).

So for this client, when we installed and configured DirSync, the Hybrid Deployment checkmark was greyed out and unavailable. At the time I figured this was just because the Forest/Domain was not prepped for Exchange 2010 SP2, and really didn’t think much of it. Well that situation didn’t take long for that greyed out option to bite us. We wanted to switch around some email addresses and first attempted via the Exchange Online Management Portal and we get an error that cannot modify Federated user properties and the changes must be made on the on-premises Active Directory user account. Well that is pretty hard seeing how none of the email addresses are able to be sync down to the AD user account.

PowerShell to the Rescue! I needed to get the EmailAddresses from the Online account replicated to the AD Account ProxyAddresses. So what I did was create a PowerShell script that does this for me.

I designed the script to run from a Server 2008 R2 domain controller. The script starts out by importing the Active Directory cmdlets. It then creates a remote PowerShell session to Exchange Online. I then have it get all of the mailboxes in Exchange Online into the variable $Mailboxes. I then loop thru each Mailbox and connect to the online mailbox using the user UPN. The script then gets the EmailAddresses from the online mailbox and sets them into the $OnlineAd variable. The script then cycles through all the email addresses and adds them to the on-prem AD account ProxyAddresses attribute.

The script is below:


import-module activedirectory

$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell/ -Credential $LiveCred -Authentication Basic -AllowRedirection

Import-PSSession $Session

$mailboxes = get-mailbox –ResultSize Unlimited

foreach ($MB in $Mailboxes)


                $UPN = $mb.UserPrincipalName

                $OnlineUser = Get-mailbox $mb.UserPrincipalName

                $OnlineAdd = $onlineUser.EmailAddresses

                foreach ($add in $OnlineAdd)


                                get-aduser -filter {UserPrincipalName -eq $UPN}|set-aduser -add @{proxyaddresses = $add}



So now my client can administer the email addresses for the Federated users by changing the ProxyAddresses attribute for the AD account.  I warned them only to change the Addresses the are have “SMTP”, the primary or reply to address, or “smtp”, the alias addresses; and ensure they do not make any changes to any other type.  I think I smell an app I could write to make the changing of only the smtp addresses via a GUI PowerShell interface.