I have a request to allow email from two email domains to be pulled into one 2013 Exchange server. I have done the required setup and have mail flowing into the server for two domains. Example would be domain1 and domain2. Domain1 is our default. I can send email to my domain2 address and I will receive this in Outlook and when looking at this closer I see Exchange converted the To field to my domain1 address as it is the default.
Next, to allow outbound email to show the from address as domain2, I setup a POP 3 account in Outlook and pointed outbound mail to the Exchange server. I also had to setup a receive connector on Exchange to accept the email from my workstation. After doing so I sent a test message to an external account. This did show the sender as my domain2 address.
This will not work for the requester and it does have severe shortcomings on the mobile side of things.
It has been years since I have looked at trust relationships for AD forests/domains but I am thinking in order to get this to work the way the requester wants I need to create a new AD forest and domain for domain2 and install a new Exchange server and create a trust between domains.
The thing I can't figure out is if using this trust can a user in domain1 pull up an email account from domain2 and do send for the domain2 address from domain1?
Is there a better way? Impossible? Any other suggestions?