Proxy auto configuration file w/ network and domain whitelisting.

proxy.pac

/**
  References:
  - *Foremost:* http://askubuntu.com/a/263596/207593
  - http://www.boinklabs.com/wpad.html#20101213
  - https://www.websense.com/content/support/library/web/v76/pac_file_best_practices$
*/

function FindProxyForURL (url, host) {
  
  // >> CONFIG >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
  
  var bypassString = "DIRECT";
  var proxyString = "PROXY proxy.company.de:3128";
  
  // Subdomains included automatically:
  var urlWhitelist = [
    "eff.org",
    "internetdefenseleague.org"
  ];
  var netWhitelist = [
    ["10.0.0.0",     "255.0.0.0"],
    ["127.0.0.0",    "255.0.0.0"],
    ["169.254.0.0",  "255.255.0.0"],
    ["172.16.0.0",   "255.240.0.0"],
    ["192.168.0.0",  "255.255.0.0"]
  ];
  
  // << CONFIG <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
  
  var host = host.toLowerCase();
  var hostIP = undefined;
  
  // whitelist URLs:
  for (var i = 0; i < urlWhitelist.length; i++) {
    var url = urlWhitelist[i]
    if (dnsDomainIs(host, "." + url)) return bypassString;
  }
  // whitelist nets:
  if (isResolvable(host)) {
    hostIP = dnsResolve(host);
    for (var i = 0; i < netWhitelist.length; i++) {
      var net = netWhitelist[i];
      if (isInNet(hostIP, net[0], net[1])) return bypassString;
    }
  }
  
  return proxyString;
}