We have a Cisco 5510 Router and I can succesfully configure port forwarding from the external interface to a port on an internal address. If I access this from the outside it works correctly, but if I access this from the inside it does not work. How do I make the internal requests resolve correctly?

Specifically I want to make a request to the externalip:external port and have it route to the internalip:internal port regardless of if the request comes from the external interface or the internal interface.

Unfortunately I cannot modify the dns entries, and as such am looking for a way to do this in the address translation of the ASA if possible.