I have an AD domain with emailaddresses of abc.com. I will be adding a couple of new users to this AD due to needing the resources, but they already have email addresses of xyz.com. The xyz.com email is hosted by an ISP and I would like to bring it in house and host it on my exchange server. However, these users need to retain the xyz.com email domain and have no reference of abc.comin their email headers. I would like the easiest/simplest method possible to accomplish this. I also was hoping to not have to add another AD in the scenario. Please help!

for your exchange system to accept mail for a domain it must be listed in a recipient policy, you can choose to define the filter so the RUS picks up these new users and automatically stamps them with @xyz.com addresses, or just define a dummy policy and manually set the addresses on the user accounts.

Ok, what I have done so far isI added a UPN for xyz.com in ADDT. Then I went ahead and created an OU in ADUC to drop these users in called xyz.com. I created a recipient policy in exchangeto affect just that OU called xyz.com in which I added the xyz.com smtp addressto the email addresses (policy) tab and made it primary. Also in the X400 connector I added xyz.com to ou1 comlumn. Of course I changed the users email addresses to the @xyz.com in ADUC. So, I have not tested yet as I have to move the mx record over. What I also have in the scenariois an smtp server internally that my exchange serverforwards all emails through the smtp connector to the smart host. So my new question is, when I request the move of my mx record to point to my smtp server, is there anything else I am missing in this scenario to make the move to point my xyz.com users to my exchange server?

HELP!!!! I am able to send email just fine with the second domain (xyz.com)I set up in the recipient policy I created. However upon receiving email from external addresses I get the following error - Action: failedStatus: 5.5.0Diagnostic-Code: smtp;530 authentication required for relay (#5.7.1) what setting is missed that is not authenticating the xyz.com incoming emails? The existing abc.com emails are just fine. Please help, i am in production and need to figure this out fast!