const dgram = require('dgram');

const server = dgram.createSocket('udp4');

server.on('message', (msg, rinfo) => {
  console.log('rinfo.address = ' + rinfo.address);
  console.log('rinfo.port = ' + rinfo.port);
  console.log(msg.toString());
  server.send(msg, rinfo.port, rinfo.address);
});

server.on('listening', () => {
  console.log('address:' + server.address().address);
  console.log('port:' + server.address().port);
});

server.bind(17601);