我们正在设置一个内部程序，在使用私有 172.30.xx 子网的内部服务器上......当我们 ping 地址 172.30.138.2 时，它通过互联网路由：
C:\>tracert 172.30.138.2
Tracing route to 172.30.138.2 over a maximum of 30 hops
1 6 ms 1 ms 1 ms xxxx.xxxxxxxxxxxxxxx.org [192.168.28.1]
2 * * * Request timed out.
3 12 ms 13 ms 9 ms xxxxxxxxxxx.xxxxxx.xx.xxx.xxxxxxx.net [68.85.xx.xx]
4 15 ms 11 ms 55 ms te-7-3-ar01.salisbury.md.bad.comcast.net [68.87.xx.xx]
5 13 ms 14 ms 18 ms xe-11-0-3-0-ar04.capitolhghts.md.bad.comcast.net [68.85.xx.xx]
6 19 ms 18 ms 14 ms te-1-0-0-4-cr01.denver.co.ibone.comcast.net [68.86.xx.xx]
7 28 ms 30 ms 30 ms pos-4-12-0-0-cr01.atlanta.ga.ibone.comcast.net [68.86.xx.xx] …