TenBrink Tech Technology | Life

Exchange – Redirect mail to "null"

Here's a fun trick that you can use sometime. I've had it in my "bag 'o fun" for years and years now. I forget the Exchange admin who taught me this trick, but I'm sure I was like 16 or 17 when I learned it.

Take the following scenario, you have a mailbox. You've created a rule in that mailbox to delete items when they arrive. That still leaves a loophole that they might sit in the deleted items folder, or you have to carry them for x days as part of the deleted item retention (dumpster).

However, for support reasons you don't want to return an NDR for that mailbox if you go and delete it. You just want the mail to disappear. Here's what you do...

Create a distribution list with no members. Turn off delivery responses and hide it from the GAL. Then, change your mailbox settings to forward all mail to the distribution list. Voila! Deleted mail without an NDR.

You can even leave the old mailbox in the GAL for that warm, fuzzy support reason, but the messages sent to it will never be seen or heard from again!

Cool, huh? Even better, this works for all versions of Exchange.

For large organizations, you might want to have several of these, and have the DL expansion take place on, or near, the mailbox server that houses the to-be-blackholed mailbox.

In Exchange 2007, you can write a transport rule to handle this task.

$cond = Get-TransportRulePredicate SentTo

$cond.Addresses = @((Get-Mailbox "mailboxalias"))

[dillon note: the Addresses parameter can contain multiple values, and types (mailbox, contact, distributionGroup). See the get-help for the New-TransportRule command for details.]

$act = Get-TransportRuleAction DeleteMessage

New-TransportRule -Name "Email Blackhole" -Comments "Messages matching this criteria passing thtrough the HT server will be dropped." -Condition @($cond) -Action @($act)

Lastly, an alternate version...if you don't need the mailbox/dl/contact to show in the GAL, add the SMTP address of the address you would like mail to disappear for to the SMTP addresses of the empty distribution list. This applies to all versions of Exchange.