如何被动检测应用代理内网的主机数

如果安装了应用代理（不是因特网共享），如何在外网通过监听数据包实现对被代理的内网主机数的判定？

我百思不得其解。

Dear sir or miss:
As a programmer, I am working in network information encryption fields. Recently, I am very dublious about one technology: Just through listening packet outside,can judge the inside network\'s computers status,such as host number etc. All these inside network\'s computer access web resource of outside network through a http-proxy running in a proxy host.
If through transparent proxy(NAT),I think it is sometime reasonable. But if through http-proxy(such socks proxy),How can we get the host information(such as host numbers) in inside network?

应用代理应该可以分析数据的IP地址来确定。
如果通过了NAT肯定是做不到了