According to the Exchange 2010 Deployment Assistant, the process is:
- you must first install one Exchange 2003 front-end server in order to provide your users with a unified namespace
- Exchange2003URL - set this parameter to the legacy DNS endpoint, for example, http://legacy.contoso.com (This parameter is only necessary when you have users with mailboxes on Exchange 2003 at the same time as users with mailboxes on Exchange 2010).
- associate the legacy host name e.g. legacy.contoso.com with your existing Exchange 2003 front-end server and associate your current host name (for example, mail.contoso.com) with your Exchange 2010 Client Access server or array - via DNS host (A) records in your internal and external DNS servers. Your end-users will not see or use this namespace. It will be used by Autodiscover and Client Access servers when redirecting legacy users to a legacy server.
- Create legacy publishing rules in your reverse proxy or firewall solution to point to your Exchange 2003 front-end server. Refer to your solution's user manual for instructions on how to do this.
So, in summary, following these steps should allow for a unified namespace for OWA + EA + Outlook Anywhere during mailbox moves without any user intervention required: (a) Install Exchange 2003 front-end server (b) set Exchange2003URL parameter for CAS array to legacy.contoso.com (c) create internal and external DNS host records pointing legacy.contoso.com to Exchange 2003 front-end server/ public IP (d) create port-forwarding/ NAT rule on corporate firewall publishing CAS array on public IP.
This suggests I don't really need a reverse proxy infrastructure, but can use port forwarding only - assuming a new Exchange 2003 front-end server is installed.
Does anyone have experience with this? Exchange 2003 to Exchange 2007 was so easy for ensuring consistent OWA + EA + Outlook Anywhere access with a unified namespace during enterprise transitions!
Thanks in advance.
IR8
