推荐一个blog

http://2hei.net/mt/2010/03/nginx-x-forwarded-for.html

例子：

         1) curl -H "X-FORWARDED-FOR" "http://-ip--" -d 

         2) curl_init()

              curl_setopt($int_curl, CURL_HTTPHEADER, 'X-FORWARDED-FOR:伪ip');