That is a great question. I have to be perfectly honest with you I like Microsoft products overall and I like Exchange, but Exchange 5.5 to Exchange 2000 or 2003 migrations are just not fun and a lot of work off hours if your in a large environment. If you do not do these type of migrations daily, I would really consider using a firm that specializes in these type of migrations. Quest, Allin, Microsoft Professional Services, CCO computing and others all have specialists that focus on this daily. They will provide you the best path for your migration and understand how to deal with any issue's that might arise ( Such as Blackberry Enterprise Server and Cisco AVVID for the Call Manger System ) integration issue's. If you decide to do this your self take a look at: http://www.microsoft.com/technet/prodtechnol/exchange/2003/library/interopmig.mspx & http://www.microsoft.com/technet/prodtechnol/exchange/2003/upgrade.mspx Sincerely, Jose Medeiros ADP | National Account Services ProBusiness Division | Information Services 925.737.7967 | 408-449-6621 CELL -----Original Message----- From: projekt8231@xxxxxxxxx [mailto:projekt8231@xxxxxxxxx] Sent: Tuesday, November 29, 2005 10:53 AM To: [ExchangeList] Subject: [exchangelist] Exchange 55 / NT4 domain migration http://www.MSExchange.org/ Hi, We are under NT4 domains (4 trusted domains) and need to migrate to AD 2003. Our Exchange 55 in NT4 domain is slow in performance and Direction is pushing heavily for the new OWA of 2003 and all its features. We plan to create a 2003 AD parallel to our NT4 domains and our first priority will be to migrate Exchange 55 to Exchange 2003 in the new 2003 AD. We will then gradually move other servers to new AD domain. What would be the recommended steps in achieving a successful exchange migration?