Application machine name vs. Web service machine name

[ChrisNorth]

Greetings,

This has me stumped.  Colleagues of mine have the following configuration.  ArcGIS Server 9.3.1, Flex Viewer 2.3.  ArcGIS Server is on a Windows machine with IIS, access if via a proxy server using Apache.

The application calls a Bing base map, and one operational layer (local).

For the sake of simplicity, "www.maps.ca" is the fictional public URL for the ArcGIS Server (that has the services and the flex application on it). Let's say the Flex application is:

http://www.maps.ca/MyMap/index.html

There is a map service on the same machine:

http://www.maps.ca/ArcGIS/rest/services/MyMapService/MapServer

It seems, the machine name of the URL in the browser has to match what the map service is in the config.xml file.  For example, if the application is:

http://www.maps.ca/MyMap/index.html

and the config.xml operational layer is:

  <layer label="My Map" type="dynamic" visible="true" alpha="1"
                   url="http://www.maps.ca/ArcGIS/rest/services/MyMapService/MapServer">   
  </layer>

... then everything works.  BUT - If the following is typed into the browser...

http://maps.ca/MyMap

.. and the config.xml contains:

  <layer label="My Map" type="dynamic" visible="true" alpha="1"
                   url="http://www.maps.ca/ArcGIS/rest/services/MyMapService/MapServer">   
  </layer>

... then the layer does not show up on the map!

The reverse is also true.  It will also fail if you type this into the browser:

http://www.maps.ca/MyMap/index.html

and the config.xml is changed to...

  <layer label="My Map" type="dynamic" visible="true" alpha="1"
                   url="http://maps.ca/ArcGIS/rest/services/MyMapService/MapServer">   
  </layer>

... then it also fails to draw!

In other words, the absence or presence of the "www" must match botht eh browser URL and the layer URL (in config.xml) for the layer to draw!

... Huh?!?!

It has to be something with the configuration of the reverse proxy, but we're stumped as to what.

Any insight is appreciated.

Chris