However, I'm still unsure where the crossdomain.xml file needs to be found.
Java�??Add crossdomain.xml to <ArcGIS_Server_Install_Location>\ArcGIS\java\manager\web_output for 10.0 or <ArcGIS_Server_Install_Location>\ArcGIS\java\web_output for 9.3 installations of ArcGIS Server. On Windows, the default locations for these directories are as follows:
Be sure that your Flex Viewer URLs in your main config.xml are using the reverse proxy urls.
In my case I have a couple of ArcGIS Servers inside the firewall. Lets same for example
I would not use those urls in my main config.xml I would use the reverse proxy urls of
And like Robert mentions if you are using a proxy server, then it would go there. Basically whatever URL your application tries to access it, is what needs the crossdomain.
David, Not sure what to tell you now... You have something setup improperly in your reverse proxy configuration. Did you follow this page? http://support.esri.com/en/knowledgebase/techarticles/detail/35894