Converting SMTP Proxy Addresses to Lowercase

Update: Be aware, this script has not been tested with SIP, X400 or other address types. I am working on an update to validate these scenarios, but in the meantime, proceed at your own risk with these address types.

I recently encountered a question in an online forum where someone asked for a script to convert all of their user’s email addresses to lower case values.  While this doesn’t affect the message delivery, it can have an impact on aesthetics when the address is displayed in an external recipient’s email client.  An Exchange Email Address Policy can do this to some degree, but I wanted to see how it could be done with PowerShell.

The challenge with a script like this is twofold:

  1. Email addresses (proxy addresses) are a multi-valued attribute, which can be tricky to work with.
  2. PowerShell is generally not case-sensitive, and therefore when we try to rename Mr. Gallalee’s email address in the screenshot below, we can see that it does not work:

WARNING: The command completed successfully but no settings of 'demolab.local/Users/Rob Gallalee' have been modified.

After a little bit of inspiration from a script written by Michael B Smith, I came up with the below:

$MailboxList = Get-Mailbox  -ResultSize unlimited

$MailboxList | % {

$LoweredList = @()
$RenamedList = @()

foreach ($Address in $_.EmailAddresses){
if ($Address.prefixstring -eq "SMTP"){
$RenamedList += $Address.smtpaddress + "TempRename"
$LoweredList += $Address.smtpaddress.ToLower()
Set-mailbox $_ -emailaddresses $RenamedList -EmailAddressPolicyEnabled $false
Set-mailbox $_ -emailaddresses $LoweredList

#Without this line the "Reply To" Address could be lost on recipients with more than one proxy address:
Set-mailbox $_ -PrimarySmtpAddress $_.PrimarySmtpAddress

This script works as follows:

  1. Puts all mailboxes into the $MailboxList variable.  If you don’t want all mailboxes,  edit the Get-Mailbox cmdlet as you see fit.
  2. Filters out X400 and other non-SMTP addresses.
  3. Creates an array called $RenamedList which stores each proxy address with “TempRename” appended to it (e.g. Rgallalee@demolab.localTempRename).
  4. Creates another array ($LoweredList) and use the “ToLower” method on each proxy address.
  5. Sets the proxy address for the user to the value of $RenamedList and then to $LoweredList.
    1. This is how we get around the case case insensitivity – name it to something else and then name it back.
  6. Step 4 and 5 don’t preserve the “Primary” / “Reply-To” address, so we set it back manually with the last line.

Note: This script turns off the email address policy for each user.

As always, feedback is welcome.

EDIT Dec 2018:
This is a similar approach, but for mailboxes migrated to Office 365. In this case, only the Primary SMTP addresses are targeted.

It may also be faster than the above, due to the fact we’re only operating against mailboxes that have uppercase (vs all of them).

Set-ADServerSettings -ViewEntireForest:$true

$TargetObjects = Get-RemoteMailbox -ResultSize Unlimited | Where {$_.PrimarySmtpAddress.ToLower() -cne $_.PrimarySmtpAddress}

Write-Host $TargetObjects.count "Remote mailboxes have one or more uppercase characters." -ForegroundColor Cyan

#Backup First
Function Get-FileFriendlyDate {Get-Date -format ddMMMyyyy_HHmm.s}
$DesktopPath = ([Environment]::GetFolderPath("Desktop") + '\')
$LogPath = ($DesktopPath + (Get-FileFriendlyDate) + "-UppercaseBackup.xml")

$TargetObjects | select DistinguishedName, PrimarySMTPAddress, EmailAddresses | Export-Clixml $LogPath
Write-Host "A backup XML has been placed here:" $LogPath -ForegroundColor Cyan

$Counter = $TargetObjects.Count

foreach ($RemoteMailbox in $TargetObjects) {

    Write-Host "Setting: " -ForegroundColor DarkCyan -NoNewline
    Write-Host $RemoteMailbox.PrimarySmtpAddress -ForegroundColor Cyan
    Write-Host "Remaining: " -ForegroundColor DarkCyan -NoNewline
    Write-Host $Counter -ForegroundColor Cyan

    Set-RemoteMailbox $RemoteMailbox.Identity -PrimarySmtpAddress ("TMP-Rename-" + $RemoteMailbox.PrimarySmtpAddress) -EmailAddressPolicyEnabled $false
    Set-RemoteMailbox $RemoteMailbox.Identity -EmailAddresses @{remove = $RemoteMailbox.PrimarySmtpAddress}

    Set-RemoteMailbox $RemoteMailbox.Identity -PrimarySmtpAddress $RemoteMailbox.PrimarySmtpAddress.ToLower()
    Set-RemoteMailbox $RemoteMailbox.Identity -EmailAddresses @{remove = ("TMP-Rename-" + $RemoteMailbox.PrimarySmtpAddress)}

    $Counter --

Write-Host "Done." -ForegroundColor DarkCyan



Combining PowerShell Cmdlet Results

In my last post I used used New-Object to create an desirable output when the “Get-Mailbox” cmdlet didn’t meet my needs.  If your eyes glazed over trying to read the script, let me make it a bit simpler by focusing on a straight forward example.

Say you need to create a list of user’s mailbox size with their email address.  This sounds like a simple request, but what you’d soon find is that mailbox sizes are returned with the Get-MailboxStatistics cmdlet and the email address is not.  For that, you need to use another cmdlet, such as Get-Mailbox.

With the New-Object cmdlet, we are able to make a custom output that contains data from essentially wherever we want.

See this example:

$MyObject = New-Object PSObject -Property @{
EmailAddress = $null
MailboxSize = $null

In this example, I have created a new object with 2 fields, and saved it as the $MyObject variable.

For now, we’ve set the data to null, as shown below:


The next step is to populate each of those fields.  We can write to them one at a time with lines like this:

$MyObject.EmailAddress = (Get-Mailbox mcrowley).PrimarySmtpAddress
$MyObject.MailboxSize = (Get-MailboxStatistics mcrowley).TotalItemSize

Note: The variable we want to populate is on the left, with what we want to put in it on the right.

To confirm our results, we can simply type the variable name at the prompt:

$MyObject with data

Pretty cool, huh?

Ok, so now about that list.  My example only shows the data for mcrowley, and you probably need more than just 1 item in your report, right?

For this, you need to use the foreach loop.  You can read more about foreach here, but the actual code for our list is as follows:

(I am actually going to skip the $null attribute step here)

$UserList = Get-mailbox -Resultsize unlimited
$MasterList = @()
foreach ($User in $UserList) {
$MyObject = New-Object PSObject -Property @{
EmailAddress = (Get-Mailbox $User).PrimarySmtpAddress
MailboxSize = (Get-MailboxStatistics $User).TotalItemSize
$MasterList += $MyObject

$MasterList with data

Finally, if you wanted to make this run faster, we really don’t need to run “get-mailbox” twice.  For better results, replace the line:

EmailAddress = (Get-Mailbox $User).PrimarySmtpAddress

With this one:

EmailAddress = $User.PrimarySmtpAddress

Exchange Proxy Address (alias) Report

Feb 2021 Edit:
Microsoft finally took down the TechNet Gallery. This script is now available on GitHub:


Exchange Server stores user’s alternate email addresses as a multi-valued attribute within Active Directory.  For example, if my colleague Jorge has jdiaz@demolab.local as well as diazj@demolab.local, his proxyAddresses attribute would look like this:

ADUC - ProxyAddresses

Notice, the capital SMTP vs. the lowercase smtp.  There can be only one uppercase SMTP, and this represents the primary, or “reply to” address.

While, it’s very easy to view someone’s proxy addresses (often called aliases, but don’t confuse it with the “alias” attribute) within the Exchange Management Console, it can be tough to work with in the Exchange Management Shell (PowerShell) due to the data being stored as a  “Multi-Valued” attribute.  The usual “Get-Mailbox” output not only shows all addresses as a single item, but in the case “mcrowley” below, we can see the shell truncates:

get-mailbox mcrowley | select emailaddresses

While there are ways (example1, example2) to manipulate this output on the screen, I recently needed to create a complete list of all users possessing one or more secondary email address, and document what those addresses were.

On the surface, this sounds simple.  We want a list of users who have more than 1 proxy address.  At first, I thought of something like this:

Get-Mailbox -Filter {emailaddresses -gt 1} | Select EmailAddresses

Get-Mailbox -Filter {emailaddresses -gt 1} | Select EmailAddresses

But we can see this doesn’t actually capture the correct users.  In the above example, LiveUser1 only has a single proxy address, but it was returned anyway.  This is because the result is actually converted to a number, and the “-gt” or “greater than” operation is done on this number; not what we want.

I have written a script to help!


  1. This script creates a CSV output of everyone’s SMTP proxy addresses.
  2. Reports to the screen the total number of users found.
  3. Reports to the screen the user(s) with the most proxy addresses.
  4. You can configure the threshold of users reported. For example, if you only wanted users with 2 or more proxy addresses included, you should change the line: “$Threshold = 0” to “$Threshold = 2”


  1. Does not currently work with Exchange Online (planned enhancement).
  2. This uses “get-recipient” with no filters by default.  You may want to  replace this with something more restrictive, like “get-mailbox”, or use the -filter parameter.
  3. Requires PS 2.0 (for Exchange 2007, see here)

Here is a sample output, shown in excel:

Sample output to screen:

The guts of this script might help with this exact scenario, or really, anywhere you want to break out and evaluate multi-valued attributes.  Feel free to use it and adjust as you see fit!

Download the script here, or copy from the text below:


1) This script Creates a TXT and CSV file with the following information:
a) TXT file: Recipient Address Statistics
b) CSV file: Output of everyone's SMTP proxy addresses.

1) Run this from "regular" PowerShell.  Exchange Management Shell may cause problems, especially in Exchange 2010, due to PSv2.
2) Usage: RecipientReportv5.ps1 server5.domain.local

1) Exchange 2010 or 2013
2) PowerShell 4.0

April 4 2015
Mike Crowley


[parameter(Position=0,Mandatory=$true,ValueFromPipeline=$false,HelpMessage='Type the name of a Client Access Server')][string]$ExchangeFQDN

if ($host.version.major -le 2) {
Write-Host ""
Write-Host "This script requires PowerShell 3.0 or later." -ForegroundColor Red
Write-Host "Note: Exchange 2010's EMC always runs as version 2.  Perhaps try launching PowerShell normally." -ForegroundColor Red
Write-Host ""
Write-Host "Exiting..." -ForegroundColor Red
Sleep 3

if ((Test-Connection $ExchangeFQDN -Count 1 -Quiet) -ne $true) {
Write-Host ""
Write-Host ("Cannot connect to: " + $ExchangeFQDN) -ForegroundColor Red
Write-Host ""
Write-Host "Exiting..." -ForegroundColor Red
Sleep 3


#Misc variables
#$ExchangeFQDN = "exchserv1.domain1.local"
$ReportTimeStamp = (Get-Date -Format s) -replace ":", "."
$TxtFile = "$env:USERPROFILE\Desktop\" + $ReportTimeStamp + "_RecipientAddressReport_Part_1of2.txt"
$CsvFile = "$env:USERPROFILE\Desktop\" + $ReportTimeStamp + "_RecipientAddressReport_Part_2of2.csv"

#Connect to Exchange
Write-Host ("Connecting to " + $ExchangeFQDN + "...") -ForegroundColor Cyan
Get-PSSession | Where-Object {$_.ConfigurationName -eq 'Microsoft.Exchange'} | Remove-PSSession
$Session = @{
ConfigurationName = 'Microsoft.Exchange'
ConnectionUri = 'http://' + $ExchangeFQDN + '/PowerShell/?SerializationLevel=Full'
Authentication = 'Kerberos'
Import-PSSession (New-PSSession @Session)

#Get Data
Write-Host "Getting data from Exchange..." -ForegroundColor Cyan
$AcceptedDomains = Get-AcceptedDomain
$InScopeRecipients = @(
$AllRecipients = Get-Recipient -recipienttype $InScopeRecipients -ResultSize unlimited | select name, emailaddresses, RecipientType
$UniqueRecipientDomains = ($AllRecipients.emailaddresses | Where {$_ -like 'smtp*'}) -split '@' | where {$_ -NotLike 'smtp:*'} | select -Unique

Write-Host "Preparing Output 1 of 2..." -ForegroundColor Cyan
#Output address stats
$TextBlock = @(
"Total Number of Recipients: " + $AllRecipients.Count
"Number of Dynamic Distribution Groups: " +         ($AllRecipients | Where {$_.RecipientType -eq 'DynamicDistributionGroup'}).Count
"Number of User Mailboxes: " + 	                    ($AllRecipients | Where {$_.RecipientType -eq 'UserMailbox'}).Count
"Number of Mail-Universal Distribution Groups: " + 	($AllRecipients | Where {$_.RecipientType -eq 'MailUniversalDistributionGroup'}).Count
"Number of Mail-UniversalSecurity Groups: " + 	    ($AllRecipients | Where {$_.RecipientType -eq 'MailUniversalSecurityGroup'}).Count
"Number of Mail-NonUniversal Groups: " + 	        ($AllRecipients | Where {$_.RecipientType -eq 'MailNonUniversalGroup'}).Count
"Number of Public Folders: " + 	                    ($AllRecipients | Where {$_.RecipientType -eq 'PublicFolder'}).Count
"Number of Accepted Domains: " + $AcceptedDomains.count
"Number of domains found on recipients: " + $UniqueRecipientDomains.count
$DomainComparrison = Compare-Object $AcceptedDomains.DomainName $UniqueRecipientDomains
"These domains have been assigned to recipients, but are not Accepted Domains in the Exchange Organization:"
($DomainComparrison | Where {$_.SideIndicator -eq '=>'}).InputObject
"These Accepted Domains are not assigned to any recipients:"
($DomainComparrison | Where {$_.SideIndicator -eq '<='}).InputObject
"See this CSV for a complete listing of all addresses: " + $CsvFile

Write-Host "Preparing Output 2 of 2..." -ForegroundColor Cyan

$RecipientsAndSMTPProxies = @()
$CounterWatermark = 1

$AllRecipients | ForEach-Object {

#Create a new placeholder object
$RecipientOutputObject = New-Object PSObject -Property @{
Name = $_.Name
RecipientType = $_.RecipientType
SMTPAddress0 =  ($_.emailaddresses | Where {$_ -clike 'SMTP:*'} ) -replace "SMTP:"

#If applicable, get a list of other addresses for the recipient
if (($_.emailaddresses).count -gt '1') {
$OtherAddresses = @()
$OtherAddresses = ($_.emailaddresses | Where {$_ -clike 'smtp:*'} ) -replace "smtp:"

$Counter = $OtherAddresses.count
if ($Counter -gt $CounterWatermark) {$CounterWatermark = $Counter}
$OtherAddresses | ForEach-Object {
$RecipientOutputObject | Add-Member -MemberType NoteProperty -Name (“SmtpAddress” + $Counter) -Value ($_ -replace "smtp:")
$RecipientsAndSMTPProxies += $RecipientOutputObject

$AttributeList = @(
$AttributeList += 0..$CounterWatermark | ForEach-Object {"SMTPAddress" + $_}

Write-Host "Saving report files to your desktop:" -ForegroundColor Green
Write-Host ""
Write-Host $TxtFile -ForegroundColor Green
Write-Host $CsvFile -ForegroundColor Green

$TextBlock | Out-File $TxtFile
$RecipientsAndSMTPProxies | Select $AttributeList | sort RecipientType, Name | Export-CSV $CsvFile -NoTypeInformation

Write-Host ""
Write-Host ""
Write-Host "Report Complete!" -ForegroundColor Green

PowerShell Tip – Running a Service Pack Report – Faster

Imagine you wanted to run a quick report of all your server’s service pack level in your domain.  After all, SP1 just came out!  You could get this information quickly by using the Active Directory Module for Windows PowerShell.  If you don’t have at least one Windows 2008 R2 (RTM or SP1) Domain Controller, you could also do something similar with the free Quest PowerShell tools, but that’s for another day…

We can find this information using a few different methods.  Here I’ll show two:

Method 1

Get-ADComputer -Properties OperatingSystem, OperatingSystemServicePack -Filter * | Where-Object {$_.OperatingSystem -like '*server*'} |  Format-Table name, oper* -autosize

You can see with Method 1, we’re telling PowerShell to get all the computer accounts from Active Directory.  Then we pass those objects over to the “Where-object” cmdlet and ask it to select only those who have an OperatingSystem attribute containing “server”.  We then format the results in a table.  Give it a try.

Not too shabby; but let’s make it better!


Get-ADComputer -Properties OperatingSystem, OperatingSystemServicePack -Filter {OperatingSystem -like '*server*'} | Format-Table name, oper* -autosize

In Method 2, we’re making smarter use of the –Filter switch.  So instead of getting ALL the computer accounts, we do our filtering up-front.  This can lead to significant amount of time saved!

How much time, you ask?  Well, we can find out with the “Measure-Command” cmdlet.  Just put any command string in {} and it will tell you how long it took to run!

Here are the results from a small environment with fast servers. 677 milliseconds isn’t bad, but when you compare it to 73, you can begin to appreciate the potential.


One last thought:  You may wish to add this extra code to make your output prettier.  It will organize your results first by operating system and then by name:

Get-ADComputer -Properties OperatingSystem, OperatingSystemServicePack -Filter {OperatingSystem -like '*server*'} | Sort-Object operatingsystem, name | Format-Table name, oper* -autosize

Script for Missing UPNs

For various reasons I’ve found myself needing to fix customer sites where the User Principal Name (UPN) was not present for AD user accounts.


Most frequently this is because the environment was once NT4, which did not require this attribute.  Whatever the reason, I’ve fixed it using PowerShell.

If you don’t have 2008 R2 domain controllers you can use the free Quest PowerShell add-ins downloaded here.

If you DO have 2008 R2 domain controllers you can use the native Active Directory Module for Windows PowerShell.

Below is a script you can use for either scenario.  This will take all users with missing UPNs from the “My Users” OU in the “contoso.local” domain and set their UPN to username@contoso.local


Get-QADUser –SearchRoot “contoso.local/My Users” -UserPrincipalName $null -SizeLimit 0 | % {$CompleteUPN = $_.samaccountname +"@contoso.local"; Set-QADUser -Id $_.DN -UserPrincipalName $CompleteUPN}

2008 R2 Native:

Get-ADUser  -Filter {-not (UserPrincipalName -like '*')} -SearchBase 'OU=My Users,DC=contoso,DC=local' | % {$CompleteUPN = $_.SamAccountName + "@contoso.local" ; Set-ADUser -Identity $_.DistinguishedName -UserPrincipalName $CompleteUPN}

Converting a Mailbox to a MailUser (and preserving your custom attributes)

It’s not often that you’ll need to convert a mailbox to a mail-user, but when you do, you’ll soon realize the steps go like this:

1. Mail-Disable the user (delete the mailbox)
2. Mail-Enable the user

So what’s the problem?  The problem is twofold:

  • First, you’ll want to automate this, and there is no “convert” button or command.  You’ll need to use PowerShell if converting multiple users.
  • Second, and perhaps more importantly, all the Exchange attributes are nullified when you delete the mailbox.  This includes CustomAttribute1-15

As we can see, you are not able to pass mailboxes to the Enable-MailUser (as you are able to do in reverse):

I’ve written a script to solve these problems.  Before you run with it, you do need to make one decision:

What do you want the mail-user’s external email address to be?

The below script takes the user’s mailbox alias and then appends  You may wish to modify this with whatever their new external address has become.

You’ll also notice I’m using a static domain controller for all configurations.  I have found in my testing, that if you do not pick the same DC for all operations, the script could out-run replication.

$DomainController = (Get-ADServerSettings).DefaultConfigurationDomainController.domain

$MailboxList= Get-Mailbox

foreach ($Mailbox in $MailboxList) {
    Disable-Mailbox -Id $mailbox.Identity -Confirm:$False -DomainController $DomainController
    Enable-MailUser -Id $mailbox.Identity -ExternalEmailAddress ($mailbox.alias +"") -DomainController $DomainController
    Set-MailUser -Id $mailbox.Identity `
     -DomainController $DomainController `
     -CustomAttribute1 $Mailbox.CustomAttribute1 `
     –CustomAttribute2 $Mailbox.CustomAttribute2 `
     –CustomAttribute3 $Mailbox.CustomAttribute3 `
     –CustomAttribute4 $Mailbox.CustomAttribute4 `
     –CustomAttribute5 $Mailbox.CustomAttribute5 `
     –CustomAttribute6 $Mailbox.CustomAttribute6 `
     –CustomAttribute7 $Mailbox.CustomAttribute7 `
     –CustomAttribute8 $Mailbox.CustomAttribute8 `
     –CustomAttribute9 $Mailbox.CustomAttribute9 `
     –CustomAttribute10 $Mailbox.CustomAttribute10 `
     –CustomAttribute11 $Mailbox.CustomAttribute11 `
     –CustomAttribute12 $Mailbox.CustomAttribute12 `
     –CustomAttribute13 $Mailbox.CustomAttribute13 `
     –CustomAttribute14 $Mailbox.CustomAttribute14 `
     –CustomAttribute15 $Mailbox.CustomAttribute15

(add more attributes if necessary, but remember that since you aren’t deleting the Active Directory object itself, most attributes remain…)