silverlight also includes classes for data access over web services, rest, windows communication foundation (wcf) services and ado.net data services. the networking support in silverlight can be used by silverlight applications to communicate using http, or at the lower socket level. cross-domain communication is supported. silverlight uses an xml-based configuration file to control the cross-domain resource-access policy, for both http and socket connections. it can be used by site administrators to control which resources a silverlight application can access, when that application did not originate in the domain of the site. in addition, silverlight also supports the adobe flash cross-domain policy file format. silverlight sockets can only initiate a connection; they cannot listen for connections.