So whats missing? This is 2nd shop I walked into.

Two AD's (Two Locations)

AD1 consositeA\UserA has all authentications good for exchange. No credidentials required for outlook (once authenticated)

AD2 consositeB\UserB always have to authenticate with exchange that is tied to AD1.

It is a two way trust between domains, however how would someone go about to fix that AD2 authenticates once with Exchange tied to AD1..

Hope this says it all?

it this 2 domains under the same forest?

or 2 separate forests?

1 domain .com under two ADs two way trusted.