获取客户端IP地址

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