The last listing is not quite correct. The correct one would be this: [root@laptop ~]# arping 192.168.24.10 -c5 ARPING 192.168.24.10 from 192.168.24.50 eth0 Unicast reply from 192.168.24.10 [52:55:55:AE:36:B4] 2.492ms Unicast reply from 192.168.24.10 [52:55:55:AE:36:B4] 1.791ms Unicast reply from 192.168.24.10 [52:55:55:AE:36:B4] 3.059ms Sent 5 probes (1 broadcast(s)) Received 3 response(s) [root@laptop ~]#