PHP获取客户端的IP地址

首先我们来了解相关变量的含义：

$_SERVER[‘REMOTE_ADDR’]：浏览当前页面的用户计算机的ip地址
$_SERVER[‘HTTP_CLIENT_IP’]：客户端的ip
$_SERVER[‘HTTP_X_FORWARDED_FOR’]：浏览当前页面的用户计算机的网关
$_SERVER[‘HTTP_X_REAL_IP’]：nginx 代理模式下，获取客户端真实IP

下面我们通过简单的代码示例来介绍PHP获取客户端IP地址的方法。
/**

• 获取客户端IP地址
  */

  function real_ip(){
      $ip = $_SERVER['REMOTE_ADDR'];
      if (isset($_SERVER['HTTP_X_FORWARDED_FOR']) && 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 = $xip;
                  break;
              }
          }
      } elseif (isset($_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_CF_CONNECTING_IP']) && preg_match('/^([0-9]{1,3}\.){3}[0-9]{1,3}$/', $_SERVER['HTTP_CF_CONNECTING_IP'])) {
          $ip = $_SERVER['HTTP_CF_CONNECTING_IP'];
      } elseif (isset($_SERVER['HTTP_X_REAL_IP']) && preg_match('/^([0-9]{1,3}\.){3}[0-9]{1,3}$/', $_SERVER['HTTP_X_REAL_IP'])) {
          $ip = $_SERVER['HTTP_X_REAL_IP'];
      }
      return $ip;
  }