[ExchangeList] Puzzling Mystery: Ex2k3 allows adding a mailbox with same name as an existing SMTP alias!

  • From: "Jabber Wock" <jabberwock99@xxxxxxxxx>
  • To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
  • Date: Mon, 28 Jan 2008 23:42:34 -0500

Hi,
 
Here is a strange situation I ran into on an Exchange 2003 server and I was wondering if anyone can shed light on it.
 
An existing user has email address Joe.Blo@xxxxxxxxxxxxxx.  And he is also configured with an existing SMTP "alias" of sales@xxxxxxxxxxxxxx.  So far so good, all is working great, for weeks and months.
 
Now a request comes to make a mailbox for sales@xxxxxxxxxxxxxx.  The admin does not realize that there is already a user with this same alias, and goes ahead and creates the new mailbox.
 
Amazingly, and here is the perplexing part:  Exchange 2003 and AD do not complain, but go ahead and allow this mailbox to be created!  So now there is a mailbox named salesd@xxxxxxxxxxxxxx and also secretly and unintentionally, an existing user with an alias sales@xxxxxxxxxxxxxx ! And of course, any emails for sales@xxxxxxxxxxxxxx go to both.
 
How and why does Exchange allow this?
 
Interestingly, Exchange does not allow the opposite sitation.  If I were to try and add sales@xxxxxxxxxxxxxx as an email SMTP alias to some other existing user Mary.Jane@xxxxxxxxxxxxxx, Exchange / AD refuses to do it as it correctly should.
 
You may want to try this just as an experiment.
 
So why is it allowed the other way?  Is this an Exchange bug or a "feature" ?
 
Best regards
JW
 

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