Universal Messaging has a built in socket policy server for Flex applications that require tcp socket or ssl socket (NSP or NSPS) protocol.

The Universal Messaging Flex API also supports tcp sockets (nsp). In the same way that the Silverlight plugin will make a client access policy file request, so too will the Adobe Flash Player make a cross domain request when a socket connection is attempted by the Universal Messaging Flex API. This means that when a Flex application is loaded and tries to make a socket request, Flash will first of all attempt to make a cross domain file request on port 843 to the host the original socket request was being made to. For example, if i specify an RNAME of nsp://myhost.mydomain.com:9000, when the Universal Messaging Flex API attempts to construct a socket on port 9000, it will first of all make a socket connect request to myhost.mydomain.com:843, and issue a cross domain file request.

So to enable successful deployment of socket based Flex Applications you need to run a policy file server on a socket interface that will automatically handle cross domain file requests. You would first need to create a socket interface on port 843, and select the "Enable Policy Server" check box under the Basic tab for an nsp interface. Once this is setup, you will also need a crossdomain.xml file in the /install/server/name/plugins/htdocs directory of the server. An example crossdomain.xml file might contain something like the following:

For further information on socket policies see Adobe's documentation on Flex Cross Domain Policy Files at http://www.adobe.com/devnet/articles/crossdomain_policy_file_spec.html.