I have two domain names that I currently use for email. They are both listed as accepted domains on my exchange server and work just fine.
What I am trying to do it make is so, if an internal email is sent to the second domain name it will not go to the exchange mailbox but get send to the users google mailbox. The google accounts have been synced, and their primary login uses the second domain name, for the users that I wish this to occur.
I have tried to setup MX records in our local DNS for the second domain to point to google but they messages still just go to the internal exchange mailbox.
I have also tried to remove the second domain as an accepted domain in exchange but it still just goes to the internal exchange mailbox.
Any suggestions, or is this even possible?
Internally, the domain name on the user account doesn't matter, it has no effect on the delivery of email. It is used for lookup on the GAL only. If Exchange matches an email address that the user has entered, then it will be sent to that mailbox.
If you want to send email to a second email address then you need to remove all references to the second domain from Exchange - so Accepted Domain, Email Address Policy and then from each mailbox. The OAB will then need to update - you can do that manually from the server and the client - or wait 48 hours.
Finally, entries need to be removed from the nicknames entries in Outlook and the users select the address internally fresh and type the external address in to the To line. Exchange should then deliver the email because it no longer recognises the address as internal. You will of course need to have MX records pointing to the Google Mail platform.
However, if you are sharing the address space, so some users internally have the domain on Google as their primary address, then you will have to setup Exchange to share the SMTP address space.