以下是一位网友总结的方法，整理得不错。只以getenv函数来判断有时会失效
PHP Code one: <? $iipp=$_SERVER["REMOTE_ADDR"]; echo $iipp; ?>
PHP Code two: <?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; ?>
///
<? 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 : $_SERVER['REMOTE_ADDR']); }
echo get_real_ip(); ?>
PHP Code three: <? //php获取ip的算法 if ($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 { $ip = "Unknown"; } echo "你的IP:".$ip ; ?>
PHP Code four: <? 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; ?>
