The ping packet in Linux returns DUP!

DUP can easily occur when the system created on the virtual machine is pinged to the Internet address! The virtual machine here is workstation, not esxi.

Returns: 64 bytes from 115.239.210.26: icmp_seq = 1 ttl = 57 time = 10 MS 64 bytes from 115.239.210.26: icmp_seq = 1 ttl = 56 time = 12 MS (DUP !) 64 bytes from 115.239.210.26: icmp_seq = 2 ttl = 56 time = 12 MS 64 bytes from 115.239.210.26: icmp_seq = 2 ttl = 56 time = 13 MS (DUP !) 64 bytes from 115.239.210.26: icmp_seq = 3 ttl = 57 time = 10 MS 64 bytes from 115.239.210.26: icmp_seq = 3 ttl = 56 time = 12 MS (DUP !) 64 bytes from 115.239.210.26: icmp_seq = 4 ttl = 56 time = 12 MS 64 bytes from 115.239.210.26: icmp_seq = 4 ttl = 56 time = 13 MS (DUP !)

(DUP !) This is an abbreviation of DUPLICATE, that is, when the ping packet receives multiple repeated response values, usually occurs in a linux environment, in windows, the ping reply is only sent to the first one, and subsequent repeated responses will be discarded.

This usually happens when the IP address of the host machine conflicts, or the gateway has repeated route settings, or the router is blocked badly. There may be other reasons.

The solution is to change the IP address segment of the host.

Recommended reading:

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Install smokeping in CentOS 6.2 to test network conditions

Iptables ping configuration in CentOS

How to ping Windows in VMware Linux

In Linux, ping the network for a long time, add a timestamp, and record the timestamp to the text.