This is going to be a bit tricky. I'm managing a small network and need to "migrate" their Exchange 5.5 server to Windows 2000. The tricky stuff follows... They have two seperate domains right now... COMPANY (NT4 domain) and CORP.COMPANY.COM (2000 AD Domain). There are duplicate copies of users because the naming convention changed... basically they created new users on the new domain and slowly moved everyone onto the new domain. To get mail they simply pointed to the old Exchange server in the old domain (the old Exchange Server mailboxes have permissions for the user account in both domains). Now that everyone is functioning in the new domain (clients) they are ready to move the Exchange Server (the last machine on the old domain). The Exchange server is currently v5.5 and is the PDC for the old COMPANY domain. The downside here is that they must use the same hardware for upgrades, but they desire new partitions and such. What I'm thinking about is using a swing method of migration and creating a new Exchange server to migrate the 50 or so mailboxes to (public folders, etc.), then rebuild the Exch5.5 server to Win2000/Exch2000 in the new CORP.COMPANY.COM domain and then migrate the mail to it's final destination. Where do I need to put the Swing Server?? Do I build an Exchange Server in the CORP domain and migrate users to it there? If I do that, how does Exchange talk to the Exchange server in a different domain (NT4 domain)? ADC? Not sure because I'm still on a learning curve with it. If that's the case then this would appear straight forward. I've never installed an Exchange 2000 server in one domain that talks with an Exchange 5.5 server in another domain, so this is where I need assistance. Thanks.