获取客户端ip：

<?php
      function getIP(){
        global $ip;
        if (getenv("HTTP_CLIENT_IP"))
            $ip = getenv("HTTP_CLIENT_IP");
        else if(getenv("HTTP_X_FORWARDED_FOR"))
            $ip = getenv("HTTP_X_FORWARDED_FOR");
        else if(getenv("REMOTE_ADDR"))
            $ip = getenv("REMOTE_ADDR");
        else $ip = "Unknow";
        return $ip;
    }
?>

获取服务器ip：

<?php
        function real_server_ip(){
        static $serverip = NULL;
        if ($serverip !== NULL){
            return $serverip;
        }
        if (isset($_SERVER)){
            if (isset($_SERVER['SERVER_ADDR'])){
                $serverip = $_SERVER['SERVER_ADDR'];
            }else{
                $serverip = '0.0.0.0';
            }
        }
        else{
            $serverip = getenv('SERVER_ADDR');
        }
        return $serverip;
    }
?>