We can forcibly prevent the Exchange 2003 server from receiving any type of traffic except TCP 80 and TCP 443, which are the ports used by HTTP and HTTPS respectively.
On the Exchange Frontend/CAS server, disable all ports except 443
Note: After you perform the above action, you do not have to restart the server. The change will take effect by doing a Disable/Enable action of Local Area Connection.
Configure Microsoft Outlook profile to connect to Exchange server using RPC over HTTPS
Note 1: In case you are repeatedly prompted to enter the Username and password, uncheck the checkbox for “Mutually authenticate the session when connecting with SSL”
Note 2: Remember to check mark “On Fast Network …. “
Try to open MS Outlook from the Run prompt using /rpcdiag switch : Outlook /rpcdiag
Your Outlook should be connected to Exchange Mailbox server using HTTPS connection.
Also verify the session status using: netstat –na