I'm working on my Exchange 2007 transition from 2003. I have a single Exchange 2007 SP1 server running on Windows Server 2008. It is in my Exchange 2003 organization and I have been able to move a few mailboxes for testing. My Exchange 2003 setup has one backend server and one frontend server. OWA works great onthe 2003 side for 2003 mailboxes. OWA is great of the 2007 side when accessing 2007 mailboxes. I want tohavea singleOWA on 2007 that can have access to both 2003 and 2007 mailboxes. I access 2007 OWA by using a URL like https://exchange.domain.com/owa or https://exchange.domain.com/exchange. It is my understanding that I must use the /exchange path for 2003 mailboxes (/owa will not work).There is no cert on the backend2003 server. I made sure that integrated authentication is in use. I added the host header to the backend 2003 server. Someone suggested that it's may not work because 2003 used http while 2007 used RPC and that because I don't have a SP on the OS it will fail. My 2003 backend server has Exchange SP2 but the OS has no service pack. Any ideas? p.s. How do I get alerting to work on this forum? The Alert Me button is checked but I still get nothing. Thanks, Patrick

This is the third time trying to post this so it will be much shorter this time. Basically, only a dedicated CAS server can be a proxy frontend to a backend 2003 server. All is working. --Patrick