title: TcpListener: Listen on every address, including GPRS IP address
body: <p>We have a simple piece of legacy software with which we need to
  communicate using TCP/IP over port 15001. We need to listen on port 15001
  for the legacy software to make a connection and then read whatever it sends us.</p>
  
  <p>We have tested this solution accross the internet and it works just fine.
  If however we test the same solution across a GPRS TCP/IP network it does not.</p>
  
  <p>All the basics have been checked, we can ping other devices in the GPRS network
  and port 15001 is not blocked by any firewall.</p>
  
  <p>So maybe there is something wrong with my TcpListener?</p>
  
  <p>It is initialized like this:</p>
  
  <pre><code>tcpServer = new TcpListener(IPAddress.Any, TCP_PORT);
  </code></pre>
  
  <p>I'm assuming it listens on every available IPv4 enabled interface on the system,
  because I used IPAddress.Any ?</p>
  
  <p>Does anybody have any idea what the difference might be between the two networks? (Even though there shouldn't be any difference) and if there is something I need to change to my TcpListener?</p>