title: Android C2DM port number choice
body: <p>I noticed that the Google C2DM (push) tcp connection uses port 5228. I also know that some firewalls block ports other than 80 443 (because of htttp and https), which causes lots of users to complain that they can't use the Market app or GTalk on their phones using their company wifi for example.</p>
  
  <p>Now my question is: why didn't Google choose port 443 or 80 for their persistent tcp connection?</p>