# A STUN client and server NPM package

## Overview
STUN (Simple Traversal of UDP through NAT: RFC3489) is a protocol that allows a client node to obtain an external IP address and port number assigned by a NAT the client is behind. It can also identify behavioral type of the NAT. It is implemented in JavaScript to run with node.js.

**(This implementation is a packaged version of https://github.com/enobufs/stun so all thanks go to him/her)**

## System requirement
* Node.js v0.4 or above
* Two IP addresses on the same machine (for server)

# How to install STUN server
    $ npm install -g stunsrv

You may need to create a symlink to node

```
#!bash
$ sudo ln -s /usr/bin/nodejs /usr/bin/node
```


## How to run STUN server

(1) execute stunsrv from the command line or
(2) create and handle a stun server through the class from a js file

 -- defaults are provided for all parameters (you'll probably need to use the first two though to do anything useful)


```
#!bash
# From terminal
$ stunsrv
$ stunsrv firstIP secondIP firstPort secondPort externalIP0 externalIP1
```


    # Or programmatically
    var stun = require('stunsrv');
    var server = stun.createServer();
    server.setAddress0("bindAddress0");
    server.setAddress1("bindAddress1");
    server.setPort0(port0);
    server.setPort1(port1);
    server.setResponseAddress0("externalIP0");
    server.setResponseAddress1("externalIP1");
    server.listen();

## How to run STUN client

    var stun = require('stunsrv');

    //var STUN_SERVER_ADDR = "dntg-stun.usrd.scea.com";
    //var STUN_SERVER_ADDR = "stun1.noc.ams-ix.net";
    var STUN_SERVER_ADDR = "172.16.4.6";

    var client = stun.createClient();
    client.setServerAddr(STUN_SERVER_ADDR);
    client.start(function(result)
    {
        var mapped = client.getMappedAddr();
        // Dump client properties
        console.log("Complete(" + result + "): " + (client.isNatted()?"Natted":"Open") + " NB=" + client.getNB() + " EF=" + client.getEF() + " (" + client.getNatType() + ") mapped=" + mapped.address + ":" + mapped.port + " rtt=" + client.getRtt());
        client.close(function()
        {
            console.log("All sockets closed.");
        });
    });

That is it!

# Limitations
* Current implementation does not support RFC 5389
* Following attributes are not supported
   * RESPONSE-ADDRESS
   * CHANGED-ADDRESS
   * USERNAME
   * PASSWORD
   * MESSAGE-INTEGRITY
   * ERROR-CODE
   * UNKNOWN-ATTRIBUTE
   * REFLECTED-FROM
   * XOR-MAPPED-ADDRESS (RFC3489bis)

# License
MIT Licensed

# CONTRIBUTORS WANTED!!
Please contact me.