get_ip.php

<?php
//传说这段代码是Discuz!中的，非常完整地表述了正常情况下访客的真实IP  
function getip() {
    if(getenv('HTTP_CLIENT_IP') && strcasecmp(getenv('HTTP_CLIENT_IP'), 'unknown')) {  
        $onlineip = getenv('HTTP_CLIENT_IP');  
    } elseif(getenv('HTTP_X_FORWARDED_FOR') && strcasecmp(getenv('HTTP_X_FORWARDED_FOR'), 'unknown')) {  
        $onlineip = getenv('HTTP_X_FORWARDED_FOR');  
    } elseif(getenv('REMOTE_ADDR') && strcasecmp(getenv('REMOTE_ADDR'), 'unknown')) {  
        $onlineip = getenv('REMOTE_ADDR');  
    } elseif(isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], 'unknown')) {  
        $onlineip = $_SERVER['REMOTE_ADDR'];  
    }  
    return $onlineip;  
}
?>