We have just installed an Exchange 2010 CAS server. Instead of moving everything and renaming and adding certificates, we merely added the CAS as a totally new name. The legacy environment has webmail.domain.com. We opted to test prior to changing our DNS entries. So for our new environment, we are using webmail2.domain.com. We have added a redirect to the legacy boxes for the 2003 mailboxes. The redirect works to the legacy boxes using a new URL (which will eventually become the legacy name during coexistence - mail.domain.com ---which is the webmail.domain.com server).
The redirect works, but the users are prompted to login twice. They login to the 2010 OWA and the redirect displays the 2003 OWA login page. I would like single sign on. Another issue is that even when testing the login, it errors out and says that the user can't be authenticated. Is it that the redirect points to a name that hasn't been added to IIS?
Forms Based Authentication is enabled on the 2003 servers as well.
I hope I explained it well enough. Essentially, we are trying to test the 2010 environment in a production environment prior to changing the DNS entries and changing certificates.