twimg.js

var http = require('http'),
    fs = require('fs');

var i = Date.now();

function run () {
  http.request({
    //host: '199.96.57.7',
    //host: '117.18.237.139',
    host: 'cs90.wac.edgecastcdn.net',
    hostname: 'pbs.twimg.com',
    port: 80,
    method: 'GET',
    path: '/favicon.ico'
  }, function (res) {
    i++;
    var imgws = fs.createWriteStream('./favicon-' + i.toString() + '.ico');
    res.pipe(imgws);
    var headers = Object.keys(res.headers).map(function (key) {
      return key + ': ' + res.headers[key];
    }).join('\n');
    fs.writeFile('./headers-' + i.toString() + '.txt', headers);
  }).end();

  setTimeout(run, 500);
}

run();