ping 命令

• Linux 系统的 ping 命令是常用的网络命令，它通常用来测试与目标主机的连通性。它通过发送 ICMP ECHO_REQUEST 数据包 到网络主机，并显示响应情况，这样我们就可以根据它输出的信息来确定目标主机是否可访问(但这不是绝对的)。有些服务器为了防止通过 ping 探测到，通过防火墙设置了禁止 ping 或者在内核参数中禁止 ping，这样就不能通过 ping 确定该主机是否还处于开启状态。

• Linux 下的 ping 和 windows 下的 ping 稍有不同，Linux 下的 ping 不会自动终止，需要按 ctrl+c 终止或使用参数 -c 来指定要求完成的回应次数。

• 命令格式 - ping [参数] [主机名或IP地址]

• 命令功能 -

  • ping 命令用于：确定网路和外部主机的状态；跟踪和隔离硬件和软件问题；测试、苹果和管理网络。如果主机正在运行并连接网上，它就对回送信号进行响应。每个回送信号包含一个网际协议(IP)和 ICMP 头，后面紧跟一个 tim 结构，以及来填写这个信息包的足够的字节。缺省情况是连续发送回送信号请求直到接收到中断信号( ctrl-c ) ；
  • ping 命令每秒发送一个数据报并为每个接收到的响应打印一行输出。ping 命令计算信号往返时间和(信息)包丢失情况的统计信息，并且在完成之后显示一个简要总结。ping 命令在程序超时或当接收到 SIGINT 信号时结束。Host 参数或者是一个有效的主机名或者是因特网地址；

• 命令参数 -

  • -d ：使用 Socket 的 SO_DEBUG 功能；
  • -f ：极限检测。大量且快速地送网络封包给一台机器，看它的回应；
  • -n ：只输出数值；
  • -q ：不显示任何传送封包的信息，只显示最后的结果；
  • -r ：忽略普通的 Routing Table ，直接将数据包送到远端主机上，通常是查看本机的网络接口是否有问题；
  • -R ：记录路由过程；
  • -v ：详细显示指令的执行过程；
  • <p>-c 数目 ：在发送指定数目的包后停止；
  • -i 秒数 ：设定间隔几秒发送一个网络封包给一台机器，默认是一秒发送一次；
  • -l 网络界面 ：使用指定的网络界面送出数据包；
  • -l 前置载入 ：设置在送出要求信息之前，先行发出的数据包；
  • -p 范本样式 ：设置填满数据包的范本样式；
  • -s 字节数 ：指定发送的数据字节数，默认值是56，加上8字节的 ICMP 头，一共是64 ICMP 数据字节；
  • -t 存活数值 ：设置存活数值 TTL 的大小；

• 命令实例 -

• 实例一：ping 的同的情况

• 命令

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  ping 192.168.120.205
  

• 输出

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  1
  [root@localhost ~]# ping 192.168.120.205
  2
  PING 192.168.120.205 (192.168.120.205) 56(84) bytes of data.
  3
  bytes from 192.168.120.205: icmp_seq=1 ttl=64 time=0.720 ms
  4
  bytes from 192.168.120.205: icmp_seq=2 ttl=64 time=0.181 ms
  5
  bytes from 192.168.120.205: icmp_seq=3 ttl=64 time=0.191 ms
  6
  bytes from 192.168.120.205: icmp_seq=4 ttl=64 time=0.188 ms
  7
  bytes from 192.168.120.205: icmp_seq=5 ttl=64 time=0.189 ms
  8
  ​
  9
  --- 192.168.120.205 ping statistics ---
  10
  packets transmitted, 5 received, 0% packet loss, time 4000ms
  11
  rtt min/avg/max/mdev = 0.181/0.293/0.720/0.214 ms
  12
  [root@localhost ~]#
  

• 实例二：ping 不同的情况

• 命令

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  ping 192.168.120.202
  

• 输出

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  [root@localhost ~]# ping 192.168.120.202
  2
  PING 192.168.120.202 (192.168.120.202) 56(84) bytes of data.
  3
  From 192.168.120.204 icmp_seq=1 Destination Host Unreachable
  4
  From 192.168.120.204 icmp_seq=2 Destination Host Unreachable
  5
  From 192.168.120.204 icmp_seq=3 Destination Host Unreachable
  6
  From 192.168.120.204 icmp_seq=4 Destination Host Unreachable
  7
  From 192.168.120.204 icmp_seq=5 Destination Host Unreachable
  8
  From 192.168.120.204 icmp_seq=6 Destination Host Unreachable
  9
  ​
  10
  --- 192.168.120.202 ping statistics ---
  11
  packets transmitted, 0 received, +6 errors, 100% packet loss, time 7005ms
  12
  , pipe 4
  13
  [root@localhost ~]#
  

• 实例三：ping 网关

• 命令

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  ping -b 192.168.120.1
  

• 输出

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  1
  [root@localhost ~]# route
  2
  Kernel IP routing table
  3
  Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
  4
  192.168.120.0   *               255.255.255.0   U     0      0        0 eth0
  5
  192.168.0.0     192.168.120.1   255.255.0.0     UG    0      0        0 eth0
  6
  10.0.0.0        192.168.120.1   255.0.0.0       UG    0      0        0 eth0
  7
  default         192.168.120.240 0.0.0.0         UG    0      0        0 eth0
  8
  [root@localhost ~]# ping -b 192.168.120.1
  9
  PING 192.168.120.1 (192.168.120.1) 56(84) bytes of data.
  10
  bytes from 192.168.120.1: icmp_seq=1 ttl=255 time=2.02 ms
  11
  bytes from 192.168.120.1: icmp_seq=2 ttl=255 time=1.83 ms
  12
  bytes from 192.168.120.1: icmp_seq=3 ttl=255 time=1.68 ms
  13
  bytes from 192.168.120.1: icmp_seq=4 ttl=255 time=1.98 ms
  14
  bytes from 192.168.120.1: icmp_seq=5 ttl=255 time=1.88 ms
  15
  ​
  16
  --- 192.168.120.1 ping statistics ---
  17
  packets transmitted, 5 received, 0% packet loss, time 4000ms
  18
  rtt min/avg/max/mdev = 1.682/1.880/2.020/0.129 ms
  

• 实例四：ping 指定次数

• 命令

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  ping -c 192.168.120.206
  

• 输出

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  [root@localhost ~]# ping -c 10 192.168.120.206
  2
  PING 192.168.120.206 (192.168.120.206) 56(84) bytes of data.
  3
  bytes from 192.168.120.206: icmp_seq=1 ttl=64 time=1.25 ms
  4
  bytes from 192.168.120.206: icmp_seq=2 ttl=64 time=0.260 ms
  5
  bytes from 192.168.120.206: icmp_seq=3 ttl=64 time=0.242 ms
  6
  bytes from 192.168.120.206: icmp_seq=4 ttl=64 time=0.271 ms
  7
  bytes from 192.168.120.206: icmp_seq=5 ttl=64 time=0.274 ms
  8
  bytes from 192.168.120.206: icmp_seq=6 ttl=64 time=0.295 ms
  9
  bytes from 192.168.120.206: icmp_seq=7 ttl=64 time=0.269 ms
  10
  bytes from 192.168.120.206: icmp_seq=8 ttl=64 time=0.270 ms
  11
  bytes from 192.168.120.206: icmp_seq=9 ttl=64 time=0.253 ms
  12
  bytes from 192.168.120.206: icmp_seq=10 ttl=64 time=0.289 ms
  13
  ​
  14
  --- 192.168.120.206 ping statistics ---
  15
  packets transmitted, 10 received, 0% packet loss, time 9000ms
  16
  rtt min/avg/max/mdev = 0.242/0.367/1.251/0.295 ms
  17
  [root@localhost ~]#
  

• 实例五：时间间隔和次数限制的 ping

• 命令

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  ping -c 10 -i 0.5 192.168.120.206
  

• 输出

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  [root@localhost ~]# ping -c 10 -i 0.5 192.168.120.206
  2
  PING 192.168.120.206 (192.168.120.206) 56(84) bytes of data.
  3
  bytes from 192.168.120.206: icmp_seq=1 ttl=64 time=1.24 ms
  4
  bytes from 192.168.120.206: icmp_seq=2 ttl=64 time=0.235 ms
  5
  bytes from 192.168.120.206: icmp_seq=3 ttl=64 time=0.244 ms
  6
  bytes from 192.168.120.206: icmp_seq=4 ttl=64 time=0.300 ms
  7
  bytes from 192.168.120.206: icmp_seq=5 ttl=64 time=0.255 ms
  8
  bytes from 192.168.120.206: icmp_seq=6 ttl=64 time=0.264 ms
  9
  bytes from 192.168.120.206: icmp_seq=7 ttl=64 time=0.263 ms
  10
  bytes from 192.168.120.206: icmp_seq=8 ttl=64 time=0.331 ms
  11
  bytes from 192.168.120.206: icmp_seq=9 ttl=64 time=0.247 ms
  12
  bytes from 192.168.120.206: icmp_seq=10 ttl=64 time=0.244 ms
  13
  ​
  14
  --- 192.168.120.206 ping statistics ---
  15
  packets transmitted, 10 received, 0% packet loss, time 4499ms
  16
  rtt min/avg/max/mdev = 0.235/0.362/1.241/0.294 ms
  17
  [root@localhost ~]# ping -c 10 -i 0.01 192.168.120.206
  18
  PING 192.168.120.206 (192.168.120.206) 56(84) bytes of data.
  19
  bytes from 192.168.120.206: icmp_seq=1 ttl=64 time=0.244 ms
  20
  bytes from 192.168.120.206: icmp_seq=2 ttl=64 time=0.195 ms
  21
  bytes from 192.168.120.206: icmp_seq=3 ttl=64 time=0.219 ms
  22
  bytes from 192.168.120.206: icmp_seq=4 ttl=64 time=0.204 ms
  23
  bytes from 192.168.120.206: icmp_seq=5 ttl=64 time=3.56 ms
  24
  bytes from 192.168.120.206: icmp_seq=6 ttl=64 time=1.93 ms
  25
  bytes from 192.168.120.206: icmp_seq=7 ttl=64 time=0.193 ms
  26
  bytes from 192.168.120.206: icmp_seq=8 ttl=64 time=0.193 ms
  27
  bytes from 192.168.120.206: icmp_seq=9 ttl=64 time=0.202 ms
  28
  bytes from 192.168.120.206: icmp_seq=10 ttl=64 time=0.211 ms
  29
  ​
  30
  --- 192.168.120.206 ping statistics ---
  31
  packets transmitted, 10 received, 0% packet loss, time 90ms
  32
  rtt min/avg/max/mdev = 0.193/0.716/3.564/1.080 ms
  33
  [root@localhost ~]#
  

• 实例六：通过域名 ping 公网上的站点

• 命令

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  ping -c 5 www.58.com
  

• 输出

  xxxxxxxxxx
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  1
  peida-VirtualBox ~ # ping -c 5 www.58.com
  2
  PING www.58.com (211.151.111.30) 56(84) bytes of data.
  3
  bytes from 211.151.111.30: icmp_req=1 ttl=49 time=14.7 ms
  4
  bytes from 211.151.111.30: icmp_req=2 ttl=49 time=16.4 ms
  5
  bytes from 211.151.111.30: icmp_req=3 ttl=49 time=15.2 ms
  6
  bytes from 211.151.111.30: icmp_req=4 ttl=49 time=14.6 ms
  7
  bytes from 211.151.111.30: icmp_req=5 ttl=49 time=19.9 ms
  8
  ​
  9
  --- www.58.com ping statistics ---
  10
  packets transmitted, 5 received, 0% packet loss, time 20101ms
  11
  rtt min/avg/max/mdev = 14.618/16.192/19.917/1.965 ms
  12
  peida-VirtualBox ~ #
  

• 实例七：多参数使用

• 命令

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  ping -i 3 -s 1024 -t 255 192.168.120.206
  

• 输出

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  [root@localhost ~]# ping -i 3 -s 1024 -t 255 192.168.120.206
  2
  PING 192.168.120.206 (192.168.120.206) 1024(1052) bytes of data.
  3
  bytes from 192.168.120.206: icmp_seq=1 ttl=64 time=1.99 ms
  4
  bytes from 192.168.120.206: icmp_seq=2 ttl=64 time=0.694 ms
  5
  bytes from 192.168.120.206: icmp_seq=3 ttl=64 time=0.300 ms
  6
  bytes from 192.168.120.206: icmp_seq=4 ttl=64 time=0.481 ms
  7
  bytes from 192.168.120.206: icmp_seq=5 ttl=64 time=0.415 ms
  8
  bytes from 192.168.120.206: icmp_seq=6 ttl=64 time=0.600 ms
  9
  bytes from 192.168.120.206: icmp_seq=7 ttl=64 time=0.411 ms
  10
  bytes from 192.168.120.206: icmp_seq=8 ttl=64 time=0.281 ms
  11
  bytes from 192.168.120.206: icmp_seq=9 ttl=64 time=0.318 ms
  12
  bytes from 192.168.120.206: icmp_seq=10 ttl=64 time=0.362 ms
  13
  bytes from 192.168.120.206: icmp_seq=11 ttl=64 time=0.408 ms
  14
  bytes from 192.168.120.206: icmp_seq=12 ttl=64 time=0.445 ms
  15
  bytes from 192.168.120.206: icmp_seq=13 ttl=64 time=0.397 ms
  16
  bytes from 192.168.120.206: icmp_seq=14 ttl=64 time=0.406 ms
  17
  bytes from 192.168.120.206: icmp_seq=15 ttl=64 time=0.458 ms
  18
  ​
  19
  --- 192.168.120.206 ping statistics ---
  20
  packets transmitted, 15 received, 0% packet loss, time 41999ms
  21
  rtt min/avg/max/mdev = 0.281/0.531/1.993/0.404 ms
  22
  [root@localhost ~]#
  

• 说明

  -i 3 发送周期为 3秒；

  -s 1024 发送包的大小为 1024；

  -t 255 TLL 值为255；