flex - What hinders NetStream.onPeerConnect from being triggered? -

i'm using adobe stratus (now renamed cirrus) build p2p application. inside application, used netstream.onpeerconnect callback function , expected triggered every time when peer connected. however, failed friend while strangely friend b managed have function called without problem.

i wondering cause issue?

here how code pieces like.

first of all, create netconnection.

netconnection = new netconnection(); netconnection.addeventlistener(netstatusevent.net_status, netconnectionhandler); netconnection.connect(server_address+developer_key); 

secondly, create netstream upon netconnection connected.

private function netconnectionhandler(event:netstatusevent):void{      switch (event.info.code){         case "netconnection.connect.success":              sendstream = new netstream(netconnection, netstream.direct_connections);             sendstream.addeventlistener(netstatusevent.net_status, netstreamhandler);              var sendobj:object = new object();             sendobj.onpeerconnect = function(subscriber:netstream) : boolean {                  trace("[onpeerconnect] far id: " + subscriber.farid);                 return true;             }              sendstream.client = sendobj;             sendstream.publish("file");             ...... 

thirdly, here's how build connection between 2 peers

    receivedstream = new netstream(netconnection, farid);     receivedstream.client = this;     receivedstream.addeventlistener(netstatusevent.net_status, incomingstreamhandler);     receivedstream.play("file"); 

please enlighten me. thanks!

it turns out friend behind symmetric nat. i'm thinking setup turn server build successful connection.