UdpSpyer.js

var udp = require('dgram');

// --------------------creating a udp server --------------------

// creating a udp server
var server = udp.createSocket('udp4');

// emits when any error occurs
server.on('error', function(error) {
    console.log('Error: ' + error);
    server.close();
});

// emits on new datagram msg
server.on('message', function(msg, info) {
    console.log('Data received from client : ' + msg.toString());
    console.log(JSON.stringify(msg.toString()));
    console.log('Received %d bytes from %s:%d\n', msg.length, info.address, info.port);

    //sending msg
    server.send(msg, info.port, 'localhost', function(error) {
        if (error) {
            client.close();
        } else {
            //console.log('Data sent !!!');
        }

    });

});

//emits when socket is ready and listening for datagram msgs
server.on('listening', function() {
    var address = server.address();
    var port = address.port;
    var family = address.family;
    var ipaddr = address.address;
    console.log('Server is listening at port ' + port);
    console.log('Server ip :' + ipaddr);
    console.log('Server is IP4/IP6 : ' + family);
});

//emits after the socket is closed using socket.close();
server.on('close', function() {
    console.log('Socket is closed !');
});

server.bind(8125, '127.0.0.1');