使用PHP获取客户端IP地址

获取访问者/客户的IP地址的最简单方法是使用

$_SERVER['REMOTE_ADDR']

$_SERVER['REMOTE_HOST']

但是，有时这不能返回访问者的正确IP地址，因此我们可以使用其他一些服务器变量来获取IP地址。

以下两个函数等效，只是在如何以及从何处检索值方面有所不同。

getenv（）用于获取PHP中环境变量的值。

// Function to get the client IP addressfunction get_client_ip() {    $ipaddress = '';    if (getenv('HTTP_CLIENT_IP'))        $ipaddress = getenv('HTTP_CLIENT_IP');    else if(getenv('HTTP_X_FORWARDED_FOR'))        $ipaddress = getenv('HTTP_X_FORWARDED_FOR');    else if(getenv('HTTP_X_FORWARDED'))        $ipaddress = getenv('HTTP_X_FORWARDED');    else if(getenv('HTTP_FORWARDED_FOR'))        $ipaddress = getenv('HTTP_FORWARDED_FOR');    else if(getenv('HTTP_FORWARDED'))       $ipaddress = getenv('HTTP_FORWARDED');    else if(getenv('REMOTE_ADDR'))        $ipaddress = getenv('REMOTE_ADDR');    else        $ipaddress = 'UNKNOWN';    return $ipaddress;}

$ _SERVER是一个数组，其中包含由Web服务器创建的服务器变量。

// Function to get the client IP addressfunction get_client_ip() {    $ipaddress = '';    if (isset($_SERVER['HTTP_CLIENT_IP']))        $ipaddress = $_SERVER['HTTP_CLIENT_IP'];    else if(isset($_SERVER['HTTP_X_FORWARDED_FOR']))        $ipaddress = $_SERVER['HTTP_X_FORWARDED_FOR'];    else if(isset($_SERVER['HTTP_X_FORWARDED']))        $ipaddress = $_SERVER['HTTP_X_FORWARDED'];    else if(isset($_SERVER['HTTP_FORWARDED_FOR']))        $ipaddress = $_SERVER['HTTP_FORWARDED_FOR'];    else if(isset($_SERVER['HTTP_FORWARDED']))        $ipaddress = $_SERVER['HTTP_FORWARDED'];    else if(isset($_SERVER['REMOTE_ADDR']))        $ipaddress = $_SERVER['REMOTE_ADDR'];    else        $ipaddress = 'UNKNOWN';    return $ipaddress;}