linux下使用ping命令判断网络的好坏

　　在linux系统里面如果想判断网络的好坏，详细脑海中蹦出的第一个命令就是ping了。ping命令基本是最常用的网络命令，它可以用来测试与目标主机的连通性。ping通过发送ICMP ECHO_REQUEST数据包到网络主机，并显示返回的相应情况，根据这些信息就可以判断目标主机是否可以访问。不过有些服务器为了防止通过ping探测到，可能会在防火墙或者内核参数中禁止ping命令，这样的话，可能虽然目标主机可以访问，但是无法ping通。需要注意linux下的ping和windows下的ping稍有区别,linux下ping不会自动终止,需要按ctrl+c终止或者用参数-c指定要求完成的回应次数。

命令格式：ping [参数] [主机名或者IP地址]。使用范例，不加任何参数，如果不加任何参数，查看是否ping通。

~ ping www.baidu.com
PING www.a.shifen.com (115.239.210.27) 56(84) bytes of data.
64 bytes from 115.239.210.27: icmp_seq=1 ttl=52 time=6.06 ms
64 bytes from 115.239.210.27: icmp_seq=2 ttl=52 time=5.56 ms
64 bytes from 115.239.210.27: icmp_seq=3 ttl=52 time=5.67 ms
64 bytes from 115.239.210.27: icmp_seq=4 ttl=52 time=5.82 ms
64 bytes from 115.239.210.27: icmp_seq=5 ttl=52 time=5.70 ms
64 bytes from 115.239.210.27: icmp_seq=6 ttl=52 time=5.79 ms
— 192.168.254.44 ping statistics —
5 packets transmitted, 5 received, 0% packet loss, time 3999ms
rtt min/avg/max/mdev = 0.152/0.159/0.172/0.017 ms

发送指定数目,可以通过 参数-c 来发送指定数目的包后停止.
~ ping www.baidu.com -c 5
PING www.a.shifen.com (115.239.211.112) 56(84) bytes of data.
64 bytes from 115.239.211.112: icmp_seq=1 ttl=52 time=6.03 ms
64 bytes from 115.239.211.112: icmp_seq=2 ttl=52 time=5.96 ms
64 bytes from 115.239.211.112: icmp_seq=3 ttl=52 time=5.79 ms
64 bytes from 115.239.211.112: icmp_seq=4 ttl=52 time=5.79 ms
64 bytes from 115.239.211.112: icmp_seq=5 ttl=52 time=6.21 ms
— www.a.shifen.com ping statistics —
5 packets transmitted, 5 received, 0% packet loss, time 4007ms
rtt min/avg/max/mdev = 5.791/5.958/6.215/0.186 ms
设定发送间隔
可以通过 参数 -c 数目：在发送指定数目的包后停止
~ ping www.baidu.com -c 5 -i 2
PING www.a.shifen.com (115.239.211.112) 56(84) bytes of data.
64 bytes from 115.239.211.112: icmp_seq=1 ttl=52 time=6.06 ms
64 bytes from 115.239.211.112: icmp_seq=2 ttl=52 time=5.84 ms
64 bytes from 115.239.211.112: icmp_seq=3 ttl=52 time=5.98 ms
^C
— www.a.shifen.com ping statistics —
3 packets transmitted, 3 received, 0% packet loss, time 4005ms
rtt min/avg/max/mdev = 5.842/5.965/6.068/0.112 ms