I would like to get some guidelines from an expert who have practically designed and configured coexisting exchange2003/2010, especially in areas of DNS /OWA /Front end server, and NATting.
for instance what Public DNS records need to be at the Registrar?
What needs to be NAtted?
what needs to be configured at the CAS server, in order to the CAS server to be able to determine if the access requested is to be redirected to Front End server or to Exchange 2010 mailboxes.
I have read some articles online , but they are not really clear about that