php獲取使用者（客戶端）真實IP地址的兩種方法

第一種方法，還算靠譜，本人以前一直用的是這個方法：

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']); 
}
 

第二種方法：

function get_real_ip(){
    static $realip;
    if(isset($_SERVER)){
        if(isset($_SERVER['HTTP_X_FORWARDED_FOR'])){
            $realip=$_SERVER['HTTP_X_FORWARDED_FOR'];
        }else if(isset($_SERVER['HTTP_CLIENT_IP'])){
            $realip=$_SERVER['HTTP_CLIENT_IP'];
        }else
 
{
            $realip=$_SERVER['REMOTE_ADDR'];
        }
    }else{
        if(getenv('HTTP_X_FORWARDED_FOR')){
            $realip=getenv('HTTP_X_FORWARDED_FOR');
        }else if(getenv('HTTP_CLIENT_IP')){
            $realip=getenv('HTTP_CLIENT_IP');
        }else{
            $realip=getenv('REMOTE_ADDR');
        }
    }
    return $realip;
}

第三種方法，摘自DISCUZ，應該還不錯吧！

// 獲取IP地址（摘自discuz）
function getIp(){
    $ip='未知IP';
    if(!empty($_SERVER['HTTP_CLIENT_IP'])){
        return is_ip($_SERVER['HTTP_CLIENT_IP'])?$_SERVER['HTTP_CLIENT_IP']:$ip;
    }elseif(!empty($_SERVER['HTTP_X_FORWARDED_FOR'])){
        return is_ip($_SERVER['HTTP_X_FORWARDED_FOR'])?$_SERVER['HTTP_X_FORWARDED_FOR']:$ip;
    }else{
        return is_ip($_SERVER['REMOTE_ADDR'])?$_SERVER['REMOTE_ADDR']:$ip;
    }
}
function is_ip($str){
    $ip=explode('.',$str);
    for($i=0;$i<count($ip);$i++){  
        if($ip[$i]>255){  
            return false;  
        }  
    }  
    return preg_match('/^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$/',$str);  
}

獲取ip地址，這裡引用thinkphp內建函式

//應網友要求，貼出 get_client_ip() 函式
/**
 * 獲取客戶端IP地址
 * @param integer $type 返回型別 0 返回IP地址 1 返回IPV4地址數字
 * @param boolean $adv 是否進行高階模式獲取（有可能被偽裝） 
 * @return mixed
 */
function get_client_ip($type = 0,$adv=false) {
    $type       =  $type ? 1 : 0;
    static $ip  =   NULL;
    if ($ip !== NULL) return $ip[$type];
    if($adv){
        if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
            $arr    =   explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
            $pos    =   array_search('unknown',$arr);
            if(false !== $pos) unset($arr[$pos]);
            $ip     =   trim($arr[0]);
        }elseif (isset($_SERVER['HTTP_CLIENT_IP'])) {
            $ip     =   $_SERVER['HTTP_CLIENT_IP'];
        }elseif (isset($_SERVER['REMOTE_ADDR'])) {
            $ip     =   $_SERVER['REMOTE_ADDR'];
        }
    }elseif (isset($_SERVER['REMOTE_ADDR'])) {
        $ip     =   $_SERVER['REMOTE_ADDR'];
    }
    // IP地址合法驗證
    $long = sprintf("%u",ip2long($ip));
    $ip   = $long ? array($ip, $long) : array('0.0.0.0', 0);
    return $ip[$type];
}

http://www.phpernote.com/php-function/322.html#