Simple DNS server in nodejs for testing purposes. Sometimes it works!

dns.js

var udp = require('dgram');
var server = udp.createSocket('udp4');
var client = null;
server.on('message', function(msg, rinfo) {
    if(rinfo.address = '127.0.0.1') {
		client = rinfo;
	} else {
		server.send(msg, 0, msg.length, client.port, client.address);
	}
	var offset = 12,
		state = 0,
		read = 0,
		remaining = 0,
		url = '';
		transaction1 = msg.readUInt8(0),
		transaction2 = msg.readUInt8(1),
		query = [];
	for(;;offset++) {
		if(state == 0) {
			remaining = msg.readUInt8(offset);
			state = 1;
			query.push(remaining);
			if(!remaining) break;
			if(url != '') { url += '.'; }
		} else {
			read = msg.readUInt8(offset);
			query.push(read);
			url += String.fromCharCode(read);
			remaining--;
			if(!remaining) state = 0;
		}
	}
	console.log(url, rinfo);
	if(!url.match(/localhost$/)) {
		return server.send(msg,0,msg.length,53,'8.8.8.8');
	}
	var ans = [transaction1, transaction2, 0x81, 0x80, 0, 1, 0, 1, 0, 0, 0, 0];
	ans = ans.concat(query, [0, 1, 0, 1, 0xc0, 0x0c, 0, 1, 0, 1, 0, 0, 1, 0x2c, 0, 4, 127, 0, 0, 1]);
	ans = new Buffer(ans);
	server.send(ans,0,ans.length,rinfo.port,rinfo.address,function(error){
		console.log('sent', ans);
	});
});
server.bind(53);