代码一：

function getip() {

  static $ip = '';

  $ip = $_SERVER['REMOTE_ADDR'];

  if(isset($_SERVER['HTTP_CDN_SRC_IP'])) {

    $ip = $_SERVER['HTTP_CDN_SRC_IP'];

  } elseif (isset($_SERVER['HTTP_CLIENT_IP']) && preg_match('/^([0-9]{1,3}\.){3}[0-9]{1,3}$/', $_SERVER['HTTP_CLIENT_IP'])) {

    $ip = $_SERVER['HTTP_CLIENT_IP'];

  } elseif(isset($_SERVER['HTTP_X_FORWARDED_FOR']) AND preg_match_all('#\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}#s', $_SERVER['HTTP_X_FORWARDED_FOR'], $matches)) {

    foreach ($matches[0] AS $xip) {

      if (!preg_match('#^(10|172\.16|192\.168)\.#', $xip)) {
        $ip = $xip;
        break;
      }

    }

  }

  return $ip;

}

代码二：

<?php
error_reporting (E_ERROR | E_WARNING | E_PARSE);
if($HTTP_SERVER_VARS["HTTP_X_FORWARDED_FOR"]){
$ip = $HTTP_SERVER_VARS["HTTP_X_FORWARDED_FOR"];
}
elseif($HTTP_SERVER_VARS["HTTP_CLIENT_IP"]){
$ip = $HTTP_SERVER_VARS["HTTP_CLIENT_IP"];
}
elseif ($HTTP_SERVER_VARS["REMOTE_ADDR"]){
$ip = $HTTP_SERVER_VARS["REMOTE_ADDR"];
}
elseif (getenv("HTTP_X_FORWARDED_FOR")){
$ip = getenv("HTTP_X_FORWARDED_FOR");
}
elseif (getenv("HTTP_CLIENT_IP")){
$ip = getenv("HTTP_CLIENT_IP");
}
elseif (getenv("REMOTE_ADDR")){
$ip = getenv("REMOTE_ADDR");
}
else{
$ip = "Unknown";
}
echo $ip;
?>

代码三：

<?php
$iipp = $_SERVER["REMOTE_ADDR"];
echo $iipp ;
?>

四：

<?php
$user_IP = ($_SERVER["HTTP_VIA"]) ? $_SERVER["HTTP_X_FORWARDED_FOR"] : $_SERVER["REMOTE_ADDR"];
$user_IP = ($user_IP) ? $user_IP : $_SERVER["REMOTE_ADDR"];
echo $user_IP
?>

五：

function get_real_ip()
{
$ip=false;
if(!empty($_SERVER["HTTP_CLIENT_IP"])){
$ip = $_SERVER["HTTP_CLIENT_IP"];
}
if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])){
$ips = explode (", ", $_SERVER['HTTP_X_FORWARDED_FOR']);
if($ip){
array_unshift($ips, $ip); $ip = FALSE;
}
for($i = 0; $i < count($ips); $i++){ if (!eregi ("^(10|172.16|192.168).", $ips[$i])){ $ip = $ips[$i]; break; } } } return($ip ? $ip : $_SERVER['REMOTE_ADDR']); } echo get_real_ip(); ?>

六：

<?php
if(getenv('HTTP_CLIENT_IP')){
$onlineip = getenv('HTTP_CLIENT_IP');
}
elseif(getenv('HTTP_X_FORWARDED_FOR')){
$onlineip = getenv('HTTP_X_FORWARDED_FOR');
}
elseif(getenv('REMOTE_ADDR')){
$onlineip = getenv('REMOTE_ADDR');
}
else{
$onlineip = $HTTP_SERVER_VARS['REMOTE_ADDR'];
}
echo $onlineip;
?>