php 获取客户端ip

方法一：（c）

function get_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(!preg_match('^(10│172.16│192.168).', $ips[$i])){
                $ip=$ips[$i];
                break;
            }
        }
    }
    return ($ip ? $ip : $_SERVER['REMOTE_ADDR']);
}

方法二：

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);
}

方法 三：

function get_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;
}