Bulk add alias on all Exchange cloud resource accounts

Question

At the moment all of our room resource accounts have the alias of @domain.co.uk - for better clarity, I'd like to create a sub-domain and add an alias of @rooms.domain.co.uk to all those accounts.

Example:

******@domain.co.uk

Alias:

******@rooms.domain.co.uk

Preferably this would be the primary SMTP address for that account and also based on the existing account name (Room123@, Room456@, etc).

Most of our resource accounts have been created in Exchange Online, not on-prem so a powershell script for this would be very helpful.

Answer 1

You can leverage the Set-Mailbox cmdlet and the -WindowsEmailAddress parameter for this:

Set-Mailbox room123 -WindowsEmailAddress ******@rooms.domain.co.uk

The above cmdlet will add ******@rooms.domain.co.uk alias and set it as primary, while preserving the previous primary SMTP as secondary one.

To do this in bulk for all rooms (remove -WhatIf once you are satisfied with the result):

Get-Mailbox -RecipientTypeDetails RoomMailbox | % { Set-Mailbox $_ -WindowsEmailAddress "$($_.Alias)@rooms.domain.co.uk" -WhatIf }