I am a It consultant and I have a customer witch use to run Windows Nt 4.0 domain and Exchange 5.5 still ..... Now have the win2k8 r2 domain up and planning to go Exchange Online Services. I know it does not says anywhere Coexsitence is not supported with exchange 5.5 but for migration purpose is there any way to kinda migrate 5 first test users online and still for the old users to gets their e-mail in exchange 5.5. As soon as I am to put my domain name online everything will go there .
What you would have to do is manually a custom recipient object for the user's Microsoft Online Account that use the Microsoft Online Routing Address. You would then set the custom recipient as the forwarding address on the Delivery Options tab of the mailbox properties. For example, let's say your user's email address is firstname.lastname@example.org. You've setup your Microsoft Online account and the domain there is company.emea.microsoftonline.com. So you create the custom recipient in Exchange 5.5 and it's SMTP address would be email@example.com. You would probably also want to hide it from the GAL. You would then go to the properties of the user's mailbox, Delivery Options tab, and set the custom recipient in the Delivery Field I think (it has been a while since I've worked with 5.5). This way any mail that comes into Exchange 5.5 for this user will be forwarded to their Microsoft Online Account.
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