➜  ~ ping
PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=55 time=7.146 ms
64 bytes from icmp_seq=1 ttl=55 time=7.228 ms
64 bytes from icmp_seq=2 ttl=55 time=7.018 ms
64 bytes from icmp_seq=3 ttl=55 time=7.243 ms
--- ping statistics ---
4 packets transmitted, 4 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 7.018/7.159/7.243/0.089 ms




PING ( 56 data bytes


  • icmp_seq:序列号,表示第几个个响应包(递增的数字)。
  • time:请求往返耗时。
  • ttl:IP数据报的ttl设置。
  • 64 bytes:响应的数据包大小是64字节。
64 bytes from icmp_seq=0 ttl=55 time=7.146 ms
64 bytes from icmp_seq=1 ttl=55 time=7.228 ms
64 bytes from icmp_seq=2 ttl=55 time=7.018 ms
64 bytes from icmp_seq=3 ttl=55 time=7.243 ms


  • 一共发送了4个ping请求,收到4个ping响应,丢包率是0%。
  • 最小/平均/最大往返时间:7.018/7.159/7.243 ms。
--- ping statistics ---
4 packets transmitted, 4 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 7.018/7.159/7.243/0.089 ms


ping命令主要基于ICMP(Internet Control Message Protocol)实现,它包含了两部分:客户端、服务器。

  • 客户端:向服务端发送ICMP回显请求报文(echo message)。
  • 服务端:向客户端返回ICMP回西显响应报文(echo reply message)。


  • 类型:1个字节。8表示回显请求报文,0表示回显响应报文。
  • 代码:1个字节。回显请求报文、回显响应报文 时均为0。
  • 校验和:2个字节。非重点,略过。
  • 标识符:2个字节。发送ICMP报文的客户端进程的id,服务端会回传给客户端。因为同一个客户端可能同时运行多个ping程序,这样客户端收到回西显报文,可以知道是响应给哪个客户端进程的。
  • 序列号:2个字节。从0开始,客户端每次发送新的回显请求时+1。服务端原样会传。
  • 数据:6个字节。客户端记录回显请求的发送时间,服务端记录回西显响应的发送时间





最后看下回显请求->响应的耗时间。请求发送时间为 May 13, 2018 18:59:14.022371000 CST,请求->响应的往返耗时为 7.092毫秒。








Echo or Echo Reply Message


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