In order to allow for "routing" or "relaying" of mail to out of office email addresses, I believe that you still need to authenticate successfully. If this condition is met, there is one checkbox that needs to be checked in the "Internet Mail Service" property page of Exchange 5.5<br>
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On the IMS Property page, click "Routing Restrictions". In the following dpopup box, make sure that "Hosts and Clients that successfully authenticate" is checked. The Exchange Mail Service will need to be restarted at this point, but that SHOULD do it<br>
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