接下來是實驗的環節了，在server端先啟動ping server

#> python ping.py

在client端發送ping

># ping 172.17.0.6
PING 172.17.0.6 (172.17.0.6) 56(84) bytes of data.
64 bytes from 172.17.0.6: icmp_seq=1 ttl=64 time=0.340 ms
64 bytes from 172.17.0.6: icmp_seq=1 ttl=64 time=1.72 ms (DUP!)
64 bytes from 172.17.0.6: icmp_seq=2 ttl=64 time=0.318 ms
64 bytes from 172.17.0.6: icmp_seq=2 ttl=64 time=0.695 ms (DUP!)
64 bytes from 172.17.0.6: icmp_seq=3 ttl=64 time=0.709 ms
64 bytes from 172.17.0.6: icmp_seq=3 ttl=64 time=0.994 ms (DUP!)

這裡就會看到有個duplicate的ping，代表一個是從系統發送的reply，一個是我們server發送的

那我們想關掉server的ping reply server呢？，在server端跑這個指令

echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all

代表我們忽略所有ping reply

如果想在對ping注入延遲，在sock.send之前讓他睡個10毫秒
time.sleep(0.01)

可以看到如下結果

># ping 172.17.0.6
PING 172.17.0.6 (172.17.0.6) 56(84) bytes of data.
64 bytes from 172.17.0.6: icmp_seq=1 ttl=64 time=10.146 ms
64 bytes from 172.17.0.6: icmp_seq=2 ttl=64 time=10.395 ms
64 bytes from 172.17.0.6: icmp_seq=3 ttl=64 time=10.923 ms