Hi, I have not done it this way before and to be sure I am not sure if it would work. But anyway we are using a CISCO ASA 500 firewall and are managing it with ASDM 6.3. What I am trying to do is access an internal URL externally by using an A record for our current domain name, but pointing it to an different internal location by Port number. For example:
from outside the network typing in www.domainname.com.au:9000
would take you to an internal URL.
Hope this makes sense.