Linux – How to find duplicate IP address?

This is a quick tip to find duplicate IP address in your local LAN network.

To find duplicate IP address, you can use arping command under linux.

Example:

#arping -D 192.168.0.10

Output:

# arping -D 192.168.0.10 132

ARPING 192.168.0.10 from 192.168.0.2 eth0

Unicast reply from 192.168.0.10 [00:0C:29:2A:3C:C7]  0.896ms

Unicast reply from 192.168.0.10 [00:0C:29:55:B7:DB]  0.923ms

Where the option -D mean: duplicate address detection mode.

In our example there is duplicate IP address in local LAN network.