Hello all, Have a quick ADC design question for you all before running in a test environment... Environment Info: I am currently running Exchange 5.5 in one Exchange Organization with 3 different Exchange sites. Each Site is in a different NT 4.0 Domain, which are connected by trusts to our Corporate Domain... We have currently upgraded the 'Corporate' domain to Win 2003 AD. This 'Corporate' 2003 AD domain has the internal Exchange 5.5 server that acts as a bridgehead with x.400 and Directory Replication Connectors to the other two Exchange 5.5 Sites. Each of those trusted Domains have only 1 Exchange 5.5 server in their Exchange site. Question: When configuring the ADC in the Corporate AD domain, I assume that I can only connect it to the local Exchange 5.5 Site (Since AD is not running in the other two domains). 1. Should each site have its own ADC connector for Replication? If so, that means that each NT 4 Domain must be upgraded to 2003 AD first... 2. Or can I setup one ADC connection to the local 5.5 site that contains the Bridgehead? If so, I assume this ADC connection will update Corporate AD with 'contacts' for accounts in the remote Exchange 5.5 sites. Will this cause any issues with Public folder permissions since the 5.5 accounts will appear as contacts? If #2 is a viable option, and I hope it is, then what happens when I have migrated all Exchange 5.5 accounts, public folders, contacts, etc to the new Exchange 2003 servers... Will I need to keep the Exchange 5.5 Bridgehead running until I can upgrade the other 2 domains to AD so they can have their own ADC's and not have to rely on updates from the Exchange 5.5 Bridgehead? Kind of confusing, but none of Microsoft's books or white papers really address this scenario. They all seem to assume that all Exchange 5.5 are in an AD environment prior to introducing the ADC. Thanks for any information or thoughts... Regards, Chris Wall Sr. Exchange Administrator MCSE, MCSA Chris.Wall@xxxxxxxxxxxxxxxxxxx T - 919.460.3236 F - 919.468.4889 Global Knowledge Network LEARNING. To Make a Difference http://www.globalknowledge.com