How to create Exchange Mail Users in bulk using ‘Enable-MailUser’, you idiots

First things first: Mail Users are NOT Mailbox Users. This is a fundamental mixup that inattentive morons seem to frequently fall foul of on Exchange forums. Creating Mailbox Users, being users who have a mailbox in your Exchange organisation, is so easy to do in bulk that it’s even in the Exchange Management Console GUI, so there’s no point in me or anyone else explaining how to do it.

Mail Users, on the other hand, are users that exist in Exchange but have an external address and no mailbox in your organisation. Unlike a Mail Contact, however, this user has an AD account in your forest. Creating these in bulk is a bit trickier and very badly documented. The reason probably stems from the fact that a) the Exchange developers hate anyone without an Exchange mailbox, and b) that the underlying PowerShell commands in Exchange 2007/2010 do not work the same way. And let’s face it, as much as I prefer a GUI for almost any admin task (due to not being a pretentious masochist), the Exchange Management Console is really just a front end for PowerShell.

• Enable-Mailbox is designed to work hand in hand with Get-User, and you can echo the output from the latter directly to the former and bulk create users using a single line of Powershell.
• Enable-MailUser, however, will not take input from Get-User, at least not directly. You also can’t get around this using foreach because of a pipelining issue.

No, a single line of PowerShell to do this is simply out of our reach. For this, we have to resort to… TWO WHOLE LINES of PowerShell:

$enableusers = Get-User -Filter {Department -Like "8*" -And RecipientType -eq "User"}
$enableusers | foreach { Enable-MailUser $_ -externalEmailAddress "$($_.name)@angrytech.com" }

This is the code I used today to automatically add mail users for all my Year 8 students (whose Department field in AD is filled in with their form, i.e. “8B”). There are plenty of other fields you can filter on. The first line retrieves the list of users, deliberately only picking User objects (not MailUser) to avoid trying to add a mail user twice. The result set of this is then enumerated by Enable-MailUser on the second line, specifying that the external email address should be made up of the AD users common name (CN) with @angrytech.com on the end, which is their (fake) email address on Google Apps.

If you already have email addresses filled in on the AD objects, and simply want to reuse this data, the second line would be as follows:

$enableusers | foreach { Enable-MailUser $_ -externalEmailAddress $_.WindowsEmailAddress.toString() }

And that’s how you get around the fact that the Exchange developers were too sodding lazy to have multiple Mail User creation in the EMC.

I still don’t like PowerShell.