List users with email forwarding enabled

Here’s a script written in response to a newsgroup post today on microsoft.public.exchange.admin.

Exchange Server allows you to forward inbound mail for one recipient to another recipient. You can forward messages to the alternate recipient, without delivering a copy to the original recipient (effectively redirecting inbound mail for the recipient), or deliver messages to both original and alternate recipients.

Figure 1: Exchange 2003 allows you to forward mail for one recipient to another recipient using Delivery Options

In Exchange 2003, this is accomplished using Delivery Options from ADUC | Exchange General tab. To forward to an external email address, create a (mail-enabled) Contact in AD.

In Exchange 2007, Delivery Options is found in the Mail Flow Settings tab in a recipient’s properties in EMC.

Listing Users With Forwarding Enabled

Requirement: List users with email forwarding enabled.
Using Saved Queries: On Windows Server 2003, this can be easily accomplished using Saved Queries. Create a new query. From the Find drop-down, select Custom Search. In the Advanced tab, type the following LDAP query:
(&(mailNickname=*)(altRecipient=*))

Figure 2:You can view recipients with forwarding enabled using ADUC’s Saved Queries feature

The other half of the requirement is to actually list the name of the user/mailbox being forwarded to. This is something ADUC can’t do – there’s no choice to add and display the altRecipient in a column next to each user.

The script will show all mailboxes setup to forward to an alternate recipient, the recipient being forwarded to (altRecipient), and also if messages are being delivered to both — the original recipient’s mailbox and the alternate recipient.

In Exchange 2010 and Exchange 2007, you can easily list this information using the shell:

Get-Mailbox -Filter {ForwardingAddress -ne $null} | ft Name,ForwardingAddress,DeliverToMailboxAndForward -Autosize

As reader Charles Howard points out in the comment (dt. Jan 29, 2009), the ForwardingAddress is output as the Active Directory object (john smith domain.net\contacts\someguy) instead of the SMTP address. The following command can output the PrimarySMTPAddress of the recipient:

Get-Mailbox -Filter {ForwardingAddress -ne
$null} | foreach {$recipient = $_; $forwardingsmtp = (Get-Recipient $_.ForwardingAddress).PrimarySmtpAddress; Write-Host $recipient.Name, $forwardingsmtp, $recipient.DeliverToMailboxAndForward }

Updates:

- 11/25/2008: Added Exchange 2007 info and command
- 2/1/2009: Added command to output primary SMTP address of recipient being forwarded to.
- 9/21/2011: Fixed script download link