mx_dnsd.js

// Example MX response with dnsd
//
// To test:
// 1. Run this program
// 2. dig @localhost -p 5353 example.com mx

var dnsd = require('dnsd')

var server = dnsd.createServer(handler)
server.zone('example.com', 'ns1.example.com', 'us@example.com', 'now', '2h', '30m', '2w', '10m')
server.listen(5353, '127.0.0.1')
console.log('Listening at 127.0.0.1:5353')

function handler(req, res) {
  var question = res.question && res.question[0]

  if(question.type != 'MX')
    return res.end()

  console.log('MX lookup for domain: %s', question.name)
  res.answer.push({'name':question.name, 'type':'MX', 'data':[10, '1.2.3.1']})
  res.answer.push({'name':question.name, 'type':'MX', 'data':[10, '1.2.3.2']})
  res.answer.push({'name':question.name, 'type':'MX', 'data':[20, '1.2.3.3']})
  res.answer.push({'name':question.name, 'type':'MX', 'data':[30, '1.2.3.4']})
  return res.end()
}