How to CORS enable ArcGIS Server 10.2.1 to Access REST Services without Using proxy.ashx?

Question

Form the ENABLE-CORS.ORG I see that editing web.config is enough to CORS enable IIS7

<?xml version="1.0" encoding="utf-8"?>
 <configuration>
  <system.webServer>
   <httpProtocol>
     <customHeaders>
       <add name="Access-Control-Allow-Origin" value="*" />
     </customHeaders>
   </httpProtocol>
  </system.webServer>
 </configuration>

Anything else I need to do, so my ArcGIS REST end points are accessible from ArcGIS JavaScript API web application without using proxy page:

esri.config.defaults.io.alwaysUseProxy = false;
esri.config.defaults.io.corsEnabledServers.push("server.organization.com");

Answer 1

i can't find a link to share right now, but as of 10.1 the self contained installation of ArcGIS Server which is typically accessible on port 6080 is CORS enabled by default (the installation also gives you the option of laying down crossdomain and clientaccesspolicy.xml files to support the same in Flex and Silverlight).

if you install the web adaptor on top of ArcGIS Server and reference your services via their new url, you have to make sure you are enabling CORS in your web server of choice (which you appear to be doing). lastly, the end user's browser has to support CORS as well.