First thing Happy New Year to all. Setup: One forest, two sub-trees, each tree has different name space (different domain domainA.edu and domainB.edu). Both domains register separately and has different external DNS to internet. Two trees connected thru Active Directory Remote Bridgehead servers. Both sides runs Exchange 2000 and connected thru Routing Group Connector. Both domains shared a class B network but each has different chunk of the class B thru sub-netting. All sub-netted networks are difined in Active Directory Sites. Question: I am the administrator of the domainB.edu only. In the event of Disaster Recovery can I just restore domainB and will both active directory and Exchange 2000 work? Assume domainA is altogether not in the picture in the DR. Has a meeting involved the whole project team, some members believe acitve directory will work but Exchange 2000 will not. Or should I create a dummy domain for domainA for the DR to work? If we can't find a solution we will call Microsoft for help on this matter. Need suggestions on the best approach for the DR so as what to discuss with Microsoft. Thanks Ong LB Exchange Admin NIE/NTU Singapore This communication (including any attachment) is meant only for the recipient(s) named above and may contain confidential or legally privileged information. If you are not an intended recipient, this communication has been sent to you in error and you must delete all copies of this communication from your computer system and notify the sender immediately by reply email. Unauthorised use, disclosure, dissemination, distribution, retention, copying or reliance on this communication is prohibited and may attract civil and/or criminal penalties. Thank you.