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# crossdomain.xml

A cross-domain policy file is an XML document that grants a web client—such as
Adobe Flash Player, Adobe Reader, etc., permission to handle data across
multiple domains. When a client hosts content from a particular source domain
and that content makes requests directed towards a domain other than its own,
the remote domain would need to host a cross-domain policy file that grants
access to the source domain, allowing the client to continue with the
transaction. Policy files grant read access to data, permit a client to include
custom headers in cross-domain requests, and are also used with sockets to
grant permissions for socket-based connections.

For full details, check out Adobe's article about the [cross-domain policy file
specification](http://www.adobe.com/devnet/articles/crossdomain_policy_file_spec.html)

Read the [Cross-domain policy file
specification](http://learn.adobe.com/wiki/download/attachments/64389123/CrossDomain_PolicyFile_Specification.pdf?version=1)
- (PDF, 129 KB)