You could migrate the accounts from NT to AD, and the combination of Active Directory Migration Tool (ADMT) and Active Directory Connector (ADC) Tools would allow you to change the login accounts to the new AD Domain while maintaining the permissions to access the old Exchange 5.5 server. It is also possible to physically run Exchange 5.5 on a Windows 2000 Member Server, though not on Windows 2003.
As a reader of this column you already know that support for NT 4.0 and Exchange 5.5 will end at the end of 2004, and that the real concern will be lack of security fixes. You may want to migrate your users to AD and Exchange 2003 now, and face the integration challenge when the parent company is ready. New Site and Server Consolidation Tools in Service Pack 1 that will make that step easier will be announced in late May at TechEd.
Dig Deeper on Exchange Server setup and troubleshooting
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