I work for the parent company that has 4 child companies that are currently autonomous and host their own AD Forests and Exchange Orgs. Our CTO wants to eventually unify the companies under a single AD/Exchange Org. This is planned for next year. In the meantime, he wants us to design a solution that will enable all our companies to be able to send and receive external mail using a single unified name. Also, need to share GAL and Calendar as well. Some of the Organizations are Exchange 2003 and some are 2007. I know we can leverage FIM for the internal GAL. I am stuck on how to have all companies send mail and receive mail as one entity as there are 4 distinct Exchange Orgs here...anything 3rd party or a hosted solution? This is obviously going to need a directory sync from all companies up to the tier that accepts the mail for mail domain name. PShafiei

I suppose we could set up a new AD Forest/Exchange 2010 server. - setup mx to deliver mail.domain.com to new Exchange Org - Sync contact objects from exisitng ADs to new AD Forest - Create connectors between the new Exchange Org to the exisitng Orgs - Configure primary smtp address (domain.com) to exisiting Exchange Orgs - set all Exchange Orgs to send outbound mail thru connector to new Org sound like a plan?? PShafiei

Hi PShafiei, Per your description, it seems a large project. Do you mean the child domain want to keep the their own AD forest and exchange org? If so, per my known, it is difficult to achieve it. Your plan seems a method, other tips for you: 1. we should set the mail.domain.com in the new org as a external relay domain 2. we should add a second smtp address as mail.domain.com for the orginal orgs, 3. it is suggest that all the orginal org emails could be relay throught new org, due to ptr reason 4. create connector between the orginal orgs and the new org Regards! Gavin TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Thanks Gavin, Yes, all (4) Orgs will maintain seperate Exchange Orgs for at least 1 year. During that time they need to be able to send/receive email using a single smtp namespace.PShafiei