I have a client that is using SBS 2003 w/exchange 2003. He has a smtp connector that is pointing to a Smarthost. He cannot send mail from Outlook 2003 to an email address in his smarthost domain ie firstname.lastname@example.org. He can send mail to anyone outside of his domain.
There are many workers that have email addresses that are not users on the SBS2003. These are the email users that he gets an NDR from.
SBS2003 users get mail OK through the Exchange.
Is the trouble on the SBS2003 or the Smarthost ISP?