Random IP address generator for anonymizing data.

anon.js

randomByte = function() {
  return Math.round(Math.random()*256);
}

randomIp = function() {
  var ip = randomByte() +'.' +
           randomByte() +'.' +
           randomByte() +'.' +
           randomByte();
  if (isPrivate(ip)) return randomIp();
  return ip;
}

isPrivate = function(ip) {
  return /^10\.|^192\.168\.|^172\.16\.|^172\.17\.|^172\.18\.|^172\.19\.|^172\.20\.|^172\.21\.|^172\.22\.|^172\.23\.|^172\.24\.|^172\.25\.|^172\.26\.|^172\.27\.|^172\.28\.|^172\.29\.|^172\.30\.|^172\.31\./.test(ip);
}


privateIps = [
  '10.0.0.0',
  '10.255.255.255',
  '172.16.0.0',
  '172.31.255.255',
  '192.168.0.0',
  '192.168.255.255'
];

publicIps = [
  '0.0.0.0',
  '255.255.255.255',
];


for (var i = 0; i < privateIps.length; i++) {
  assert(isPrivate(privateIps[i]), privateIps[i] + ' should be private, but is considered public!');
}

for (var i = 0; i < publicIps.length; i++) {
  assert(!isPrivate(publicIps[i]), privateIps[i] + ' should be public, but was considered private!');
}

Thanks