ping.php

<?php
$URL = "www.yahoo.com";
$ref = "www.test.it";

$fp = fsockopen($URL, 80, $errno, $errstr, 30);

$header = array(
    'GET / HTTP/1.1',
    'Host: ' . $URL,
    'Referrer: ' . $ref,
    'Connection: Close'
);

fputs($fp, join("\r\n", $header) . "\r\n\r\n");

$data = "";
while (!feof($fp)) $data.=fgets($fp,64000);
fclose($fp);

print $data;

?>