Exchange 2010 – forward email to external contact without keeping the original mailbox calendar


Here's an interesting one that I can't figure out. I was about to call MS, but figured I'd check here first.


Two Exchange 2010 forests federated with GAL Sync.

User had a mailbox on Exchange 2010 server.

Bob now has a new mailbox on a different Exchange forest (

Bob wants his old email forwarded for to

So…easy enough right? Create a contact in the Exchange server and set the forwarding on the mailbox and for grins hide the mailbox from the address books. Done, right?

Wrong (sort of)…because (note: I have federation and GAL sync allowing free/busy across forests):

Bob is getting auto-forwarded meeting requests from who used the Scheduling assistant and typed in "" and saw that he's available. He gets the calendar forward and says "Um…Sally…I'm booked at that time" to which she replies "not from what I see".

Now if Bob is available on and he accepts, it shows up on his calendar as it should. But Sally sees the request still sent to in the scheduling assistant as he is free but is coming to the meeting.

SO…basically users in the organization can still see free/busy details on the old calendar for the mailbox even though the mailbox is hidden from the GAL.


Since I can't create a contact and then forward that contact….is there any way around the above? I don't think I can remove a calendar from a mailbox. I considered removing all calendar permissions but wasn't sure if that was the right path to go down or not.

OR even better: Can someone tell me how to accept email for on Exchange without having a mailbox for him and then re-route it to

UPDATE: I have figured out how to handle the calendar with removing the default permissions…it's an ok fix. The BOUNTY will be for the "OR EVEN BETTER" question in bold. If it isn't possible, then that doesn't count as BOUNTY worthy. 🙂 Thank you!

Best Answer

The solution is to set up SMTP namespace sharing between the two Exchange servers.