A custom DNS server in NodeJS that saves off queries to Firebase so they can be retrieved later. Accompanying blog post: http://5f5.org/ruminations/dns-debugging-over-http.html

firedns.js

var crypto = require('crypto');
var dns = require('native-dns');
var rest = require('restler');

var server = dns.createServer();

server.on('request', function (request, response) {
  var domain = request.question[0].name;
  if(domain == 'webutils.flourishworks.com') {
    // Don't log this because it can't be uniquely identified and subsequently retrieved
    response.answer.push(dns.CNAME( { name: domain, data: 'ghs.googlehosted.com.', ttl: 30 }));
    response.send();
  }
  else {
    var sha256 = crypto.createHash('sha256').update(domain).digest("hex");
    rest.postJson('http://firedns.firebaseio.com/'+sha256+'/.json',
      { poweredBy: 'Firebase',
        timestamp: new Date().getTime(),
        header: request.header,
        question: request.question,
        address: request.address}
      ).on('complete', function() {
        response.answer.push(dns.CNAME( { name: domain, data: 'ghs.googlehosted.com.', ttl: 30 }));
        response.send();
      });
   }
});

server.on('error', function (err, buff, req, res) { console.log(err.stack); });
server.serve(53);