PHP伪造页面referer来源地址几种方法

$opt=array('http'=>array('header'=>"Referer: $refer")); 
$context=stream_context_create($opt); 
$file_contents = file_get_contents($url,false, $context);

$ch = curl_init(); 
curl_setopt ($ch, CURLOPT_URL, "http://www.phprm.com"); 
curl_setopt ($ch, CURLOPT_REFERER, "http://www.phprm.com/"); 
curl_exec ($ch); 
curl_close ($ch);

$server = 'www.phprm.com'; 
$host = 'www.phprm.com'; 
$target = 'index.php'; 
$referer = 'http://www.phprm.com/'; // Referer 
$port = 80; 
$fp = fsockopen($server, $port, $errno, $errstr, 30); 
if (!$fp){ 
  echo "$errstr ($errno)\n"; 
}else{ 
$out = "GET $target HTTP/1.1\r\n"; 
$out .= "Host: $host\r\n"; 
$out .= "Referer: $referer\r\n"; 
$out .= "Connection: Close\r\n\r\n"; 
fwrite($fp, $out); 
while (!feof($fp)){ 
echo fgets($fp, 128); 
} 
fclose($fp); 
}

<?php 
echo "<hr />"; 
echo $_SERVER["HTTP_REFERER"];