Question

I have a few IPs (other servers hosting large binary files) and their static IP.

When a user clicks on a link, I want to ping each server until it finds one that is online and redirect the browser to the appropriate URI. If none of the servers are online, it should display an error.

Answer 1

look at this….
Ping site and return result in PHP

function availableUrl($host, $port=80, $timeout=10) { 
  $fp = fSockOpen($host, $port, $errno, $errstr, $timeout); 
  return $fp!=false;
}

//Return "true" if the url is available, false if not.
echo availableUrl("www.google.com");