I would like to add a new Exchange 2007 CAS server to our AD site because of some OWA issues I'm experiencing on our current CAS server. We are running Exchange 2007 SP3 Update Rollup 10. We are eventually planning to upgrade to 2013 but I need to get this resolved quickly. I would like to go over the steps I believe I need to take and verify with the Experts-Exchange community that I'm not missing anything.
1. Update my UC certificate with an additional internal name of the new CAS server. Apply this new cert to all current Exchange servers.
2. Install Exchange 2007 SP3 and Update rollup 10
3. Add UC cert to new CAS server
4. Remove the external URL from OWA, Exchange ActiveSync, OAB Distribution in the Exchange Management console from the old CAS server and add to the new one.
5. Update DNS
If I end up decommissioning the old CAS server completely, then I'll also need to modify the autodiscover DNS entry to point to the new CAS server. The current CAS server also holds the HT role, I plan to put this on the new CAS server as well and will update send/receive connectors too.