When deploying the Lucity Web Map, the web server that hosts Lucity Web must be able to talk to the web server that hosts ArcGIS Server. If both of these applications are on the same server, no further setup is required. However, when Lucity Web and Arc Server are hosted on separate servers (which is common), administrators must create either a ClientAccessPolicy.xml or a CrossDomainPolicy.xml. Silverlight will always first attempt to check for and download a ClientAccessPolicy.xml file. If it cannot find it, Silverlight will look for a CrossDomain.xml file.
Automatic Configuration
ArcGIS Server 10.1 and higher can configure this relationship automatically using the ArcGIS Web Adaptor.
Manual Configuration
One or both of these XML files MUST be placed on the ArcGIS Server in the root folder in which ArcGIS is installed. For example:
ArcGIS Server is installed to C:\inetpub\wwwroot\ArcGIS\Manager - Place these files in C:\inetpub\wwwroot
ArcGIS Server is installed to C:\inetpub\gisroot\ArcGIS\Manager - Place these files in C:\inetpub\gisroot
The presence of the ClientAccessPolicy.xml and CrossDomainPolicy.xml files opens a hole in the ArcGIS Server machine's security that allows Silverlight applications on other servers to communicate with ArcGIS Server. The type of policy an agency applies dictates which types of machines allowed to communicate with ArcGIS Server.
Policy examples are provided below. Feel free to copy, paste, and modify these examples.