I have a full exchange 2007 setup with CAS, Hub transport and mailbox roles on a different servers. I brought up a new server running exchange 2010 on the internal network running the CAS, Hub transport and mailbox roles. I got the mailboxes servers talking to each other but is there anyway to get the CAS to talk to each other. Is there anyway to make the 2007 CAS as the primary access point for all users? Right now the 2010 CAS is only on the internal network and has no access to the outside like the 2007 CAS.