title: Java Server and Client work local but not over ip
body: <p>I wrote a Simple Java Server-Client program. It works all fine when I use "localhost" as address in the Socket's constructor, but it fails when I specify my actual IP. Thus I think the problem is not in the Java-code. 
  I've forwarded the Ports on my Router (a Speedport w921v from the German provider Telekom). On Windows 7 I've turned down every Firewall. I tried as well on Ubuntu 14. I use really the correct ip and not a local ip like 127. or 192.. When typing <code>sudo netstat -tulpe</code> I find this record which might belong to my program </p>
  
  <pre><code>tcp        0      0 *:10300                 *:*                     LISTEN      
  </code></pre>
  
  <p>10300 was the port I gave the Server with <code>server = new ServerSocket(10300);</code></p>
  
  <p>When I try to communicate with the port via <code>telnet xx.xxx.xx.xxx 10300</code> I can't get no response but if I type <code>telnet localhost</code> 10300 I will get an answer.</p>
  
  <p>I have really no clue why this problem occurs.</p>
  
  <p>Sorry for the bad English ;)</p>