ping一个ip怎么会收到的成功回复不是来自那个ip呢？

Question

root@localhost:~# ping 10.0.0.200  
PING 10.0.0.200 (10.0.0.200) 56(84) bytes of data.  
64 bytes from 111.161.77.196: icmp_req=14134 ttl=44 time=261 ms  
64 bytes from 111.161.77.196: icmp_req=3281 ttl=44 time=262 ms  
64 bytes from 111.161.77.196: icmp_req=7178 ttl=44 time=270 ms  
64 bytes from 111.161.77.196: icmp_req=12577 ttl=44 time=261 ms  
64 bytes from 111.161.77.196: icmp_req=7771 ttl=44 time=259 ms  
64 bytes from 111.161.77.196: icmp_req=7773 ttl=44 time=258 ms  
64 bytes from 111.161.77.196: icmp_req=14136 ttl=44 time=257 ms  
64 bytes from 111.161.77.196: icmp_req=3287 ttl=44 time=268 ms  
64 bytes from 111.161.77.196: icmp_req=17068 ttl=44 time=265 ms  
^C  
--- 10.0.0.200 ping statistics ---  
9 packets transmitted, 9 received, 0% packet loss, time 8009ms  
rtt min/avg/max/mdev = 257.896/262.977/270.902/4.329 ms  
root@localhost:~# ping 10.0.0.201  
PING 10.0.0.201 (10.0.0.201) 56(84) bytes of data.  
64 bytes from 10.0.0.201: icmp_req=1 ttl=64 time=313 ms  
64 bytes from 10.0.0.201: icmp_req=2 ttl=64 time=307 ms  
64 bytes from 10.0.0.201: icmp_req=3 ttl=64 time=306 ms  
64 bytes from 10.0.0.201: icmp_req=4 ttl=64 time=320 ms  
64 bytes from 10.0.0.201: icmp_req=5 ttl=64 time=279 ms  
64 bytes from 10.0.0.201: icmp_req=6 ttl=64 time=267 ms  
^C  
--- 10.0.0.201 ping statistics ---  
7 packets transmitted, 6 received, 14% packet loss, time 6007ms  
rtt min/avg/max/mdev = 267.497/299.031/320.009/18.781 ms  

两台设备用pptp vpn连接同一个pptpd服务器，第一个openwrt路由，第二个手机，奇怪第一个为什么不是从10.0.0.200收到的回复呢？已经可以通过openwrt爬墙