A client is using example.dyndns.org to point to their public WAN interface which is used for external Exchange access to their Windows 2003 server. However, devices from within their internal network can't use that address to connect to Exchange from within the internal network. What we need to do is setup DNS on the Windows server to point to the internal IP of the server for example.dyndns.org. That way a user can use Exchange on their mobile device without ever changing a setting. I've tried doing that a few ways but it's not working.
Public: example.dyndns.org -> 220.127.116.11
Internal: example.dyndns.org -> 192.168.1.10