title: Possible reasons for failure http connection between two servers?
body: <p>I have 3 shared hosting servers, server 1, server 2 and server 3
  server 1 and 2 both run the same php version 5.6,</p>
  
  <p>The following script checks if server 3 is reachable by the executing servers 1 and 2,</p>
  
  <pre><code>$url= "http://www.lhp.layalisolutions.com"; 
  
  if (isDomainAvailible($url))
         {
                 echo $url." is up and running!";
         }
         else
         {
                 echo $url." is not reachable!";
         }
  
         //returns true, if domain is availible, false if not
         function isDomainAvailible($domain)
         {
                 //check, if a valid url is provided
                 if(!filter_var($domain, FILTER_VALIDATE_URL))
                 {
                         return false;
                 }
  
                 //initialize curl
                 $curlInit = curl_init($domain);
                 curl_setopt($curlInit,CURLOPT_CONNECTTIMEOUT,10);
                 curl_setopt($curlInit,CURLOPT_HEADER,true);
                 curl_setopt($curlInit,CURLOPT_NOBODY,true);
                 curl_setopt($curlInit,CURLOPT_RETURNTRANSFER,true);
  
                 //get answer
                 $response = curl_exec($curlInit);
  
                 curl_close($curlInit);
  
                 if ($response) return true;
  
                 return false;
         }
  </code></pre>
  
  <p>executing this script on server 1 yield server 3 is up and running!
  <a href="http://hmmosoft.com/wbsrvs/WEbSrvcTest.php" rel="nofollow">http://hmmosoft.com/wbsrvs/WEbSrvcTest.php</a></p>
  
  <p>executing this script on server 2 yield server 3 is not reachable!
  <a href="http://www.layaligroup.com/imgOGs/WEbSrvcTest.php" rel="nofollow">http://www.layaligroup.com/imgOGs/WEbSrvcTest.php</a></p>
  
  <p>What could possibly cause this script to yield different results on these two diefferent servers? is there a way to determine if it's a server 2 or server 3 issue?</p>
  
  <p>This is not a curl related issue, as even the simple <code>file_get_contents</code> function fails to retrieve any response from server 3 when running on server 2, and no matter what method I use on server 2, I always fail to get any response from server 3.  </p>
  
  <p><strong>EDIT</strong>
  The script was runnig fine on both server 1 and 2, and this problem recently apeared from nowhere!</p>