title: React Native - how does the app determine the packager IP address, not found on device
body: <p>I have a react native app, if I run it on the iOS simulator it works and can connect to the running packager that is running on localhost:8081, however if I try to run the app on an actual iOS device, it fails because it can't load the js bundle because it can't find the packager service. </p>
  
  <p>My device and my dev server are on the same WIFI network, how does the app determine where the pacakger service lives?  If I modify the AppDelegate.m file and replace:</p>
  
  <pre><code>jsCodeLocation = [[RCTBundleURLProvider sharedSettings] jsBundleURLForBundleRoot:@"index.ios" fallbackResource:nil];
  
  //with an explicit IP address, then the app works:
  
  jsCodeLocation = [NSURL URLWithString:@"http://192.168.0.9:8081/index.ios.bundle?platform=ios&amp;dev=true"];
  </code></pre>
  
  <p>Any tips on settings I may need to modify for running on an actual device, without having to explicitly modify this file.</p>
  
  <p>Thanks.</p>