title: P2P connection over all NAT types
body: <p>Recently I am working on a p2p application and i found out how to program UDP holepunching with c# using ICE and STUN protocols.</p>
  <p>Its good but there is some limits for symmetric NATs and routers using symmetric NAT.\</p>
  <p>I am looking for a way to connect two system over any NAT type .</p>
  <p>Anyway I have tried UPNP and port forwarding too but due to firewall and router blacklist this option is out of my mind, if its your answer please describe how should I use this method correctly.</p>
  <p>Thanks in advance.</p>