1. 獲取ip地址

2. 與允許的ip范圍 進行比較?

代碼如下：

$ip = getIP();

function getIP()

{

? ?$onlineip = '';

? ?if(getenv('HTTP_CLIENT_IP') && strcasecmp(getenv('HTTP_CLIENT_IP'), 'unknown'))

? ?{

? ? ? ?$onlineip = getenv('HTTP_CLIENT_IP');

? ?} else if (getenv('HTTP_X_FORWARDED_FOR') && strcasecmp(getenv('HTTP_X_FORWARDED_FOR'), 'unknown')) ? ?{

? ? ? ?$onlineip = getenv('HTTP_X_FORWARDED_FOR');

? ?} else if (getenv('REMOTE_ADDR') && strcasecmp(getenv('REMOTE_ADDR'), 'unknown')) {

? ? ? $onlineip = getenv('REMOTE_ADDR');

? ?} else if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], 'unknown')) {

? ? ? $onlineip = $_SERVER['REMOTE_ADDR'];

? ?}

? ?preg_match("/[\d\.]{7,15}/", $onlineip, $onlineipmatches);

? ?$onlineip = empty($onlineipmatches[0]) ? 'unknown' : $onlineipmatches[0];

? ?return $onlineip;

}