I have two new 2010 CAS servers. I'm trying to use them to front end an Exch 2007 mainbox server. I get a 403 error when I try to connect to the 2010CAS OWA URL I've copied the 2007 OWA files from the 2007 server to both 2010 CAS servers and restarted IIS. What am I missing? --Patrick

I've copied the 2007 OWA files from the 2007 server to both 2010 CAS servers and restarted IIS. Why did you do that? That isn't correct, that is why things aren't working. For co-existence with Exchange 2007 or older, both Exchange 2010 and Exchange 2007 need to be exposed to the Internet with unique URLs. The correct external URLs must be configured. Exchange 2010 will not proxy Exchange 2007, all it will do is redirect - hence the need for the older server to be exposed as well. You have probably broken your CAS servers, so I would suggest that you remove Exchange from them, then wipe them and rebuild them. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

I did that because this document said to. http://msexchangeteam.com/archive/2009/11/20/453272.aspx I'll remove the files. It's just a directory and is easy to undo. How is the redirect configured? --Patrick

If you read those instructions again, you will find that it states that you only copy the content across when you have non-Internet facing CAS servers. You cannot use that method to remove the requirement for Exchange 2007 CAS servers completely, which is how your question reads. In the article I have linked to below it explains why this doesn't work - Exchange 2010 does not proxy OWA for Exchange in the same AD site. Therefore you would need to have a functioning Exchange 2007 mailbox and CAS servers in another AD site to use that technique. This page explains how to configure the proxy and redirection. http://technet.microsoft.com/en-us/library/bb310763.aspx Simon.Simon Butler, Exchange MVP Blog | Exchange Resources