Hello all, I am on a fact-finding mission in preparation for an Exchange upgrade to occur later in the year. I was wondering if any of you can provide some insight. Information: [in the form of a Microsoft Certification question :-) ] You are the administrator of an NT 4.0 network.... Currently our North America operations has 3 main NT 4.0 domains that are all connected via trusts. The exchange infrastructure is Exchange 5.5. We have one Exchange Organization and 3 different Exchange Sites (one for each domain). Due to mission critical services that are ONLY compliant with NT 4.0, the current Corporate HQ domain can not be upgraded to AD. Instead, we are planning on creating a New seperate AD domain to be hosted in the HQ datacenter (so there will be one NT4.0 domain and a Win 2003 AD domain hosted from the same site). Slowly we will move users over to the new domain and leave their accounts active on the old NT 4.0 domain until the services can be replaced with 2003 compliant applications... Questions: If I implement Exchange 2003 in the new domain, could I configure it to use the same domain (@globalknowledge.com) as the existing Exchange 5.5 infrastructure? I guess my main question is - is it possible to create trusts between the new AD domain with the old NT4.0 domains so that mail can be received by Exchange 2003 and routed to mailboxes that currently exist in the Exchange 5.5 setup? Vice Versa, I would like to have any e-mails that are created on the exchange 5.5 mailboxes in the remote locations to be sent out through the new Exchange 2003 setup - until the remote domains can be brought in as OU's or the domain has been upgraded to 2003 AD as well. Is this where the ADC comes into play? I appreciate your reply and any information that would point me to an upgrade path similar to this.