Q. I run quite large network with different subnets. I’d like to know how can I find out duplicate IP address under Linux / UNIX?
A. You can use arpping command. The arping utility performs an action similar to ping command, but at the Ethernet layer. You can send ARP REQUEST to a neighbor host / computers.
-I eth0 : Specify network interface i.e. name of network device where to send ARP REQUEST packets. This option is required.
The -D option specifies duplicate address detection mode (DAD). It returns exit status 0, if DAD succeeded i.e. no replies are received.
Be aware that there is an arping as part of the iproute2 package, and this arping is present on Red Hat systems when newly installed – and perhaps others.
This version is available from Thomas Habets.
thanks for pointing out more information about arping. I believe they follows same syntax.
Can you please show to find [MAC flapping] same mac address being learned on different ports . usually to trouble shoot this we collect mac table multiple time and find the single mac address being learned on different ports .My colleague are using some tool but they want to share it with me.
How can I find out if my Ethernet card (NIC) is being recognized or not?