title: How to tell if Apple Push Notification Service APNS is alive
body: <p>We are testing an application that has APNS and have noticed that sometimes the APNS service for the sandbox environment stops "pushing".  The message is successfully received by the apple server, no errors. There are no incoming messages from the feedback service either (we have successfully received feedback on other things). Our codebase for this feature has not changed in a while and has been working rock solid.</p>
  
  <p>My question is, does Apple have some kind of ping that we can send to let us know that the sandbox APNS is alive and working?</p>
  
  <p>Thanks.</p>