配置Nginx 拒绝代理访问

##通过分析，在后端发现其代理访问过来的数据都是两个IP的，默认情况下直接访问获取真实IP，其IP只有一个，而通过手机 3G\4G上网则是2个IP，不过有匿名IP的话，到服务器则只有一个IP，这种就不太好判断了...
[root@ipython conf]# tail -f /var/log/nginx/logs/access.log  | grep ahtax
120.193.47.34 - - [26/Sep/2014:23:34:44 +0800] "GET /ahtax/index.html HTTP/1.0" 503 1290 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36" "10.129.1.254, 120.193.47.34"

[root@ipython conf]# cat /%path%/self_.php
<!--?php 
if ($_SERVER["HTTP_X_FORWARDED_FOR"]!="")
{
    $user_ip=$_SERVER["HTTP_X_FORWARDED_FOR"];
}elseif($_SERVER["HTTP_X_REAL_IP"]!=""){
    $user_ip=$_SERVER["HTTP_X_REAL_IP"];
}else{
        $user_ip=$_SERVER["REMOTE_ADDR"];
}
echo $user_ip."
<?php
if ($_SERVER["HTTP_X_FORWARDED_FOR"]!="")
{
??? $user_ip=$_SERVER["HTTP_X_FORWARDED_FOR"];
}elseif($_SERVER["HTTP_X_REAL_IP"]!=""){
??? $user_ip=$_SERVER["HTTP_X_REAL_IP"];
}else{
??????? $user_ip=$_SERVER["REMOTE_ADDR"];
}
echo $user_ip."";
??????? foreach($_SERVER as $key=>$value)
??????????????? echo $key."\t"."$value"."";
?>

首先需要有一个正则来匹配日志里的两个IP,Nginx正则依赖pcre库...
[root@ipython conf]# pcretest 
PCRE version 7.8 2008-09-05
  re> '^\d+.\d+.\d+.\d+\W\s\d+.\d+.\d+.\d+$'
data> 192.168.1.1, 1.1.1.1
 0: 192.168.1.1, 1.1.1.1
Nginx配置文件在location $dir 中加入条件来匹配http_x_forwarded_for:
#proxy
if ($http_x_forwarded_for ~ '^\d+.\d+.\d+.\d+\W\s\d+.\d+.\d+.\d+$'){
    return 503;
}