Get-ForwardedMailboxes.ps1

<#
    .SYNOPSIS
    Retrieves all mailboxes from Exchange that have automatic forwarding configured at the mailbox level.

    .DESCRIPTION
    Author: James Schlackman <[email protected]>
    Last Modified: Sep 19 2025

    .PARAMETER OutputPath
    Path to optional CSV export file.
#>

#Requires -Modules ExchangeOnlineManagement

Param(
    # Export file name
    [Parameter()] [ValidateNotNullOrEmpty()] [String]$OutputPath = ('{0:yyMMdd} Forwarded Mailboxes.csv' -f (Get-Date))
)

Import-Module ExchangeOnlineManagement

# Connect to Exchange Online if not already connected
If (!(Get-ConnectionInformation)) {
    Connect-ExchangeOnline
}

$allFwds = Get-Mailbox -Filter {ForwardingAddress -ne $null -or ForwardingSmtpAddress -ne $null}

$resultOutput = $allFwds | Select DisplayName,Alias,RecipientTypeDetails,Identity,ForwardingAddress,ForwardingSmtpAddress

# Show in grid
Write-Host 'See grid export for details and select records for export.'
$resultExport = $resultOutput | Out-GridView -OutputMode Multiple -Title 'Select records for export to CSV'

# Export selected records to file
If ($resultExport) {
    Write-Host 'Exporting to ' -NoNewline
    Write-Host $OutputPath -ForegroundColor Green
    $resultExport | Export-Csv -NoTypeInformation -Path $OutputPath -Encoding UTF8
}