UDP / TCP Hole Punching ( Symmetric Nat )

If you don't know about TCP, UDP hole punching, don't bid. If You have not done any P2P application then it is less likely you can do it successfully. I need a proof of concept or working code for TCP and UDP hole punching Symmetric Nat. Here is the scenerio. (1) I have a central server X with public IP address. (2) 2 clients (A, B) connect with central server from two different countries with private IP address which are behind Any type of firewall or router.( Symmetric Nat ) (3) Central server will pass the public IP of A to B, public IP of B to A. (3) Server A will connect directly to Server B with the information it received from central server. (4) A and B are connected and without any more help from they can communicate using TCP or UDP protocol. (5) Able to send both each other simple "10 Mb File" to other [login to view URL] behind Symmetric Nat. Implements both protocol or at least One protocol.( Symmetric Nat ) Before any payment project should be successfully tested using clients which is behind firewall and located in different network ( Symmetric Nat ). Note if you dont have time not apply for job.