//经过复杂的判断与算是的获取ip地址函数
 function getip() {
        if (getenv('http_client_ip')) {
                        $ip = getenv('http_client_ip');
                }
                elseif (getenv('http_x_forwarded_for')) {
                        $ip = getenv('http_x_forwarded_for');
                }
                elseif (getenv('http_x_forwarded')) {
                        $ip = getenv('http_x_forwarded');
                }
                elseif (getenv('http_forwarded_for')) {
                        $ip = getenv('http_forwarded_for');
}
                elseif (getenv('http_forwarded')) {
                        $ip = getenv('http_forwarded');
                }
                else {
                        $ip = $_server['remote_addr'];
                }
                return $ip;
 //最简单获取ip地址代码一句实例
$reip=$_server[remote_addr];
 echo $reip;
//
//php教程获取ip的算法
  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;
  //可以分出内网与外网站ip地址获取程序
function getip_out(){
 $ip=false;
 if(!empty($_server[http_client_ip])){
  $ip = $_server[http_client_ip];
 }
 if (!empty($_server['http_x_forwarded_for'])) {
  $ips教程 = explode (, , $_server['http_x_forwarded_for']);
  if ($ip) { array_unshift($ips, $ip); $ip = false; }
  for ($i = 0; $i    if (!eregi (^(10│172.16│192.168)., $ips[$i])) {
    $ip = $ips[$i];
    break;
   }
  }
 }
 return ($ip ? $ip : $_server['remote_addr']);
 }
echo getip_out();
//php获取ip的算法，用了？号表达式来处理
$user_ip = ($_server[http_via]) ? $_server[http_x_forwarded_for] : $_server[remote_addr];
  $user_ip = ($user_ip) ? $user_ip : $_server[remote_addr];