I have a user on a domain on site that is using a Windows Server 2000 domain controller. I have an Exchange 2007 server on another domain with a Windows Server 2003 domain controller. I want to set up a linked mailbox for that user on the Exchange server, but when I try to do this I'm given an error that says it's not compatible with a Server 2000 domain controller. We already have several users with linked mailboxes on that domain as is, so clearly it can and has been done. What am I missing here?