I am preparing an Exchange and AD migration / merge between two AD Domains and Exchange Org due to a recent merger / acquisition of another company. I am in the middle of an Exchange 2007 to Exchange 2013 migration whcih may complicate things:
Let me give you some background:
Domain A - "My Company" - Where all the mailboxes and AD accounts will eventually reside. We are mostly Exchange 2007 SP3 UR13, but we have Exchange 2013 SP1 set up, and are migrating accounts to 2013 as we speak. Domain is 2003 Native Mode.
Domain B - "The other company" - Where all the "other" mailboxes and AD accounts currently are. They are Exchange 2010 SP3 UR5. Domain is 2003 Native Mode.
I currently have a two-way transitive trust set up between Domain A and Domain B. The trust is working, users from either domain can log onto PC's on the other domain without issue. DNS resolution is fully functional between domains. Mapped drives happen,
group policy runs, everything is good, except Outlook.
However, when users from either domain try to log into Exchange from a PC on the opposite domain, they get an error which says "The connection to Microsoft Exchange is Unavailable. Outlook must be online or connected to complete this action". It appears autodiscover is not allowing connection to the other domain. I can resolve autodiscover.DomainA.com from a DomainB.com computer, and vice versa.
So question is, do I have to do something inside of Autodiscover for it to resolve or forward autodiscover requests from one domain to another? I would say I am fairly competent at Exchange, but this is something I am unfamiliar with.