How does centos server execute ping command?

To turn off the firewall settings, avoid the firewall prohibiting ping or prohibiting ping in kernel parameters, so that it is impossible to determine whether the host is still on by pinging.

Command to specify the number of ping:

1, [root @ Li Wentong ~] # ping-c 4? www.baidu.com

Ping www.a.shifen.com (115.239.210.27) 56 (84) bytes of data.

64 bytes come from115.239.210.27: icmp _ seq =1TTL = 56 time = 17.5 ms- you can see the time from the start to the receipt of the return message.

64 bytes from115.239.210.27: icmp _ seq = 2ttl = 56time =18.6ms.

64 bytes from115.239.210.27: icmp _ seq = 3ttl = 56time =17.9ms.

64 bytes from115.239.210.27: icmp _ seq = 4ttl = 56time =17.8ms.

2. [root @ Li Wentong ~] # Ping-i3-C5-S1024 www.baidu.com

Ping www.a.shifen.com (115.239.210.26)1024 (1052) bytes of data. -"Ping Baidu, interval of 3 seconds, size 1024.

1032 bytes come from115.239.210.26: icmp _ seq =1TTL = 56time =18.8ms.

1032 bytes from115.239.210.26: icmp _ seq = 2ttl = 56time =19.6ms.

1032 bytes from115.239.210.26: icmp _ seq = 3ttl = 56time =18.2ms.

1032 bytes come from115.239.210.26: icmp _ seq = 4ttl = 56time =17.5ms.

1032 bytes come from115.239.210.26: icmp _ seq = 5ttl = 56time =19.1millisecond.

3. [root @ Li Wentong ~] # ping? 192. 168.4 1. 10 1

Ping192.168.41.1kloc-0/(192.168.41. ? -"indicates that the target network is unreachable, but it is not.

From192.168.41.48 icmp _ seq = 2, the target host is inaccessible.

From192.168.41.48 icmp _ seq = 3, the target host is unreachable.

From192.168.41.48 icmp _ seq = 4, the target host is inaccessible.

From192.168.41.48 icmp _ seq = 5, the target host is unreachable.

From192.168.41.48 icmp _ seq = 6, the target host is inaccessible.

From192.168.41.48 icmp _ seq = 7, the target host is unreachable.