Email non-delivery in exchange 2003

Posted on 2010-01-04
Last Modified: 2013-11-30
Having a problem with mail delivery for one user.  We are using SBS 2003 &  Ex2003 and have had to continue our use of an external POP3 provider.  Mail directed to an internal  user that does not have an account on our SBS /  exchange system ( BUT does have an account on the POP3 provider system  ( is not being delivered to the POP3 provider.  We instead get an NDR report.  

I cannot change his email address (  A contact record results in a server bounce. I am unable to deploy OWA in the short term.

How can I get the mail originating internally for this individual to be delivered to the POP3 system?
Question by:sfsrm
    LVL 58

    Accepted Solution


    You need to split your SMTP namespace. Have all mail delivered to Exchange, but tell Exchange what to do when it gets a message addressed to a contact it doesn't know about. This essentially means entering the name (or IP) of the POP3 host's server.

    Take a look at


    Author Comment

    The solution proposed is exactly correct for my situation.  Many Thanks!

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