I don’t know about you, but I’m planning on removing my old Exchange and I can’t be bothered to flap about backend and front-end, redirects and all that crap. As I move my users from 2003 to 2007 I want a nice easy transition. Outlook does this fine and copes, but obviously OWA changes.
Rather than worry about certificates, I decided just to open up another port for external and push that through to the new Exchange server. To do this, do the following:
1) On your Router, go to NAT and set port forwarding to be external port 4444 to go to your Exchange servers IP and port 443.
2) On your MSExchange server, open IIS Admin, right click “Default Web Site”, properties. Set the HTTPS port to 4444. Apply, OK. Fire up a CMD window and type “iisreset /restart /noforce”.
3) Open Exchange Management Console, Server Configuration, Client Access, choose the server in the top pane and then open the properties of OWA in the bottom pane. Set the External URL to https://your_ip:4444/owa
Click Apply, OK.
That’s it, you should now be able to navigate to your external IP/owa on port 4444 and open mailboxes on that exchange box without a hitch.