dgram-test.js

var dgram = require('dgram');

console.log('step 1');
dummy(function () {
  console.log('step 2');
  tester(function () {
    console.log('step 3');
  });
});

function dummy(callback) {
  var socket = dgram.createSocket('udp4');

  socket.bind(5000, '0.0.0.0');

  socket.once('listening', function () {
    socket.setBroadcast(true);
    socket.setMulticastLoopback(true);
    socket.addMembership('224.0.0.1', '0.0.0.0');

    socket.close();
  });

  socket.once('close', callback);
}

function tester(callback) {
  var socket = dgram.createSocket('udp4');

  socket.bind(5000, '0.0.0.0');

  socket.once('listening', function () {
    socket.setBroadcast(true);
    socket.setMulticastLoopback(true);
    socket.addMembership('224.0.0.1', '0.0.0.0');

    var data = new Buffer('text');
    socket.send(data, 0, data.length, 5000, '224.0.0.1', function (err) {
      if (err) throw err;
    });
  });

  socket.once('message', function (data) {
    console.log('got message');

    socket.close();
  });

  socket.once('close', callback);
}