By default,Flash Player (and AIR content that is not in the AIR application sandbox)first looks for a URL policy file named crossdomain.xml inthe root directory of the server, and looks for a socket policyfile on port 843. A file in either of these locations is calledthe master policy file . (In the case of socket connections,Flash Player also looks for a socket policy file on the same portas the main connection. However, a policy file found on that portis not considered a master policy file.)