title: Status checker for hundreds IP addresses
body: <p>I wonder how to make a status checker, checking about 500 addresses in a few minutes?
  (it'll check a certain port if its listening).</p>
  
  <p>But I care about the performance... so I don't know if it can be done with PHP. Waiting for your suggestions guys.</p>
  
  <p>Also please give me some examples, if you think that the best way for this thing will be PHP or C#.</p>
  
  <p>Ofc. I meant the TCP connection but not http, since I need to check open port for example: <em>11740</em></p>
  
  <p>Edit:</p>
  
  <p>Added third bounty for this question! Please post some better answer than those already posted.</p>