So companyB acquires companyA and will eventually all be under domain of companyB. Down the road, the goal is to have an exchange environment with users from both companies on the B domain.
Right now, we have A users able to send and receive on B domain through combination of AD contacts in domain B and public address of A in B spf record so that part works.
What we are trying to do now is have the ability to view calendars (free/busy) and GAL from B on the A domain. I have looked around a bit and found that it doesn't seem to be that easy. A is 2003 and B is 2007 (later we'll merge both to 2010). I understand the first part is to get the ipsec tunnel working and forest trust setup between A and B. The exchange part could be an issue. I've found a posting suggesting to use microsoft inter-org utility but it would only work for public folders; doesn't solve the GAL issue. Has anyone had to do this before? If I were to use it for free/busy, would the 2007 B server need a pf store (for 2003 compatibility so our server can see it)?