常用php函数[03]：取得客户端IP地址

1. <?php
2. function GetIP(){
3.             if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))
4.                   $ip = getenv("HTTP_CLIENT_IP");
5.             else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))
6.                   $ip = getenv("HTTP_X_FORWARDED_FOR");
7.             else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))
8.                   $ip = getenv("REMOTE_ADDR");
9.             else if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))
10.                   $ip = $_SERVER['REMOTE_ADDR'];
11.             else
12.                   $ip = "unknown";
13.             return($ip);
14. }
15. ?>