How to make a connection between a webplayer and an external application?

I am working on a web-based simulation environment which can be controlled via the network. I have an application written with python, which sends string commands to webplayer. However, none of the examples that I tried so far made this happen. In some of them I got a crash (when I used Zero-MQ library on both sides) or the others I got "no valid crossdomain policy found" error.

I don't have to much experiment with unity3d and especially with networking. I put the crossdomain file in both webplayer and application root folder, but still not working.

Do I miss some code to search for the crossdomain file? Should I need to use some build-in networking code?

I really appreciate it, if you could share your ideas or experiment about this particular situation.