title: What is gradle sync in Android Studio?
body: <p>What is it? And what does it do?
  I'm working on an enterprise that has a proxy, and it fails trying to connect to somewhere.
  Why does it needs internet connection? What ports does it use?</p>
  
  <p><strong>EDIT:</strong> The answer of the user Caleb was perfect. I would like to add that the proxy should be configured too in the gradle.properties. Something like this:</p>
  
  <p><code>systemProp.http.proxyHost=*proxyAddress*</code></p>
  
  <p><code>systemProp.http.proxyPort=*portNumber*</code></p>
  
  <p><code>systemProp.https.proxyHost=*proxyAddress*</code></p>
  
  <p><code>systemProp.https.proxyPort=*portNumber*</code></p>