PHP獲取客戶端IP地址函數

function getip(){     if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))         $ip = getenv("HTTP_CLIENT_IP");     else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))         $ip = getenv("HTTP_X_FORWARDED_FOR");     else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))         $ip = getenv("REMOTE_ADDR");     else if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))         $ip = $_SERVER['REMOTE_ADDR'];     else         $ip = '000.000.000.000';         return($ip); }