I had this working in the past. Our server crashed and had to be rebuilt.
I had alternate email accounts for my users through Exchange using a different domain name- built into SBS2003
Example (made up domain name):
My current business domain: ABCDEFGHIJKL.COM
I changed the MX/a records to point to my exchange server with the registra I purchased the domain from.
The owner realized that it's hard to communicate the above domain name for his companies emails - Joeexample@ABCDEFGHIJKL.COM to his clients.
He purchases another domain name: ABC.COM from a different registra.
I connected to that registra an pointed the MX/a records to my server@ABCDEFGHIJKL.COM and our static IP
I went into the Server manager within SBS 2003
I opened a the user properties and choose the E-Mail Addresses tab
I created a new SMTP account using the newly purchased domain name
Example: Chris@ABC.COM
I get this message when I attempt to send an email:
Your message cannot be delivered to the following recipients:
Recipient address: Chris@ABC.com
Reason: Remote SMTP server has rejected address
Diagnostic code: smtp;550 5.7.1 Unable to relay for Chris@ABC.com
Remote system: dns;server@ABCDEFGHIJKL.COM (TCP|xxx.xxx.x.xxx|40174|xx.xx.xx.xxx|25)
What am I doing wrong? What did I forget to do?
If I'm correct you can even just add the new domain to the default policy (just make sure that you don't set the new domain as default) and you're off :-)
Basically, you add the new domain als an alternative domain to the default policy.
Grts,
Michael