Simply list all Shared Mailboxes from On-premises and in Exchange Online with PowerShell

Hey there, fellow tech enthusiasts!
Today, I have some lines to drop about how to simply list all your shared mailboxes.

In this case I wanted to get all email addresses.

Step 1: Connect to your environment

Connect to you on-premises Exchange environment.

Step 2: Retrieve On-Premises Shared Mailboxes

Let's start by fetching all the remaining shared mailboxes from your on-premises environment. Open up your PowerShell console and execute the following:

$OnPremSharedMailboxes = Get-Mailbox -RecipientTypeDetails SharedMailbox -ResultSize unlimited | Select-Object PrimarySmtpAddress

Step 3: Retrieve the remote shared mailboxes

Run the following commands

Get all mailboxes

  $RemoteMailboxes = Get-RemoteMailbox -ResultSize unlimited

Get all remotesharedmailboxes and filter only the smtpaddress

  $RemoteMailboxes | Where-Object { $_.RecipientTypeDetails -eq "RemoteSharedMailbox" } | select PrimarySmtpAddress

Step 5: Consolidate the Results

It's time to bring everything together and create a unified list of shared mailboxes. Run the following commands to consolidate the on-premises and Exchange Online results:

  $AllSharedMailboxes = $OnPremSharedMailboxes + $ExchangeOnlineSharedMailboxes

With this command, you'll combine the arrays of on-premises and Exchange Online shared mailbox addresses into a single array called '$AllSharedMailboxes'. You can make other choices in your filter to generate a different list.

Step 6: Display the Results

  $AllSharedMailboxes

And just like that, your PowerShell console will present you with a complete list of shared mailbox addresses, combining the best of both on-premises en Exchange Online.