We are looking at implementing Exchange 2007 for an organisation which currently has 5 -7 sites all with differant AD domains. And also differant email domains. We were thinking along the lines of getting 3 servers in a hosted environment, and having all clients connect to the exchange system via https\RPC over a private VPN. Roles of the servers would be 1.DC 2.Client Access (Front End) 3.Mailbox My question is how do I structure my exchange & AD design for this deployment. I was thinking of the following options. 1. One AD domain with multiple recipent policiesfor each of the differant email domains. 2. One Forest with multiple AD Domains If someone knows could they please tell me what they think my AD design should look like, or if they have a better way of designing this then I would appreciate some feedback. Thanks,

Hi, Yes this sounds OK. Effectively you would be as you say setting up a hosted Exchange environment. I believe this should be done with a single domain in a single forest. If the sites need to be kept separate then you would need to consider different GALs and Address Lists (including offline address lists) for each site. You would need more than three servers to put this together as well, although I guess you know that. Just wondering, why has the organisation got different AD domains in different sites? Are they in a single forest? Would they be better consolidating and adding Exchange to their existing setup? Cheers Nathan