Using arping to know ip-MAC mapping

You can use arping to know IP address to MAC address mapping of your local network. Usage is simple:

arping  [-AbDfhqUV]  [-c count] [-w deadline] [-s source] -I interface destination

For example, you may use the command as below:

$ arping -I eth0 10.0.0.1
ARPING 10.0.0.1 from 10.0.0.2 eth0
Unicast reply from 10.0.0.1 [11:22:33:44:55:66]  0.123ms
Unicast reply from 10.0.0.1 [11:22:33:44:55:66]  0.251ms
...

Secret of the tool is ARP protocol [1]. To know the MAC address of the machine that has a specific IP address, IP protocol layer uses the protocol. MAC address that found in this way can be used to communicate with Ethernet protocol layer. arping just sends the ARP REQUEST to local network neighbour.

It could be useful in case of internet connection problem if IP duplication is suspicious.

[1] http://www.erg.abdn.ac.uk/users/gorry/course/inet-pages/arp.html