I am migrating from Exchange 2003 to 2010, I would like to setup co-existance and followed the instructions for setup on technet. OWA redirects without issue, the problem I have is with RPC/HTTPS. Exchange 2003 mailboxes and connect directly to the Exchange 2003 server using RPC/HTTPS and Exchange 2010 mailboxes can connect through the Exchange 2010 CAS with RPC/HTTPS. The problem is if I try to use the 2010 CAS to proxy the RPC/HTTPS connections to Exchange 2003, Outlook never connects.
My UCC cert is valid and contains the external name as well as the legacy.domain.com I have tried switch IIS security to basic as was suggested on the technet forums
If anyone has any ideas I could try please let me know. Or even if they could point me to the right log files to see where the connection is failing on the CAS.
Enable Integrated Auth on the 2003 RPC/HTTPS virtual directory.