File Transfer between two computer behind a firewall/router (with private IP addresses) over internet

File Transfer between two computer behind a firewall/router (with private IP addresses) over internet THIS APPLICATION NEEDS TO WORK OVER INTERNET - NOT JUST INTRANET/LAN. SO IF IT WORKS ON YOUR PC THAT IS NOT ENOUGH. IT NEEDS TO WORK OVER ROUTERS/SWITCHES. Skills Needed: TCP/IP, Networking, Routers, IP, Routing, DNS, OPEN DNS, SOCKETS, Java Delivery: Create an application in Java that communicates over the internet. i.e. If I run the application from my local PC - behind a personal router/firewall; another application needs to be able to connect to it. Deliver this as a demo FTP application working behind a firewall. Usecase: Two computers need to exchange files. The file sender becomes a server. The file receiver become a Client. Client and Server are implemented using Apache FTPServer in Java. - This code is available from apache already. No work required here. The Client and Server can sit behind a firewall or Home-Router (e.g. WiFI Routers or Switcheds) - As a result the Home PC will get a private IP ([login to view URL] etc….) The application needs to be smart enough to know where to connect. You will need sound knowledge on JXTA - STUN, P2P, NAT Translation, TCP/IP, UDP The application needs to be in Java.