Duplicate IP false alerts from arping

[unni krishnan <unnikrishnan.a@gmail.com>]

Hi,

I am trying to find a duplicate IP in the network using arping.

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[root@vps1 ~]# ping -c 3 192.168.1.212
PING 192.168.1.212 (192.168.1.212) 56(84) bytes of data.
64 bytes from 192.168.1.212: icmp_seq=1 ttl=64 time=1.33 ms
64 bytes from 192.168.1.212: icmp_seq=2 ttl=64 time=0.280 ms
64 bytes from 192.168.1.212: icmp_seq=3 ttl=64 time=0.306 ms

--- 192.168.1.212 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 0.280/0.641/1.339/0.494 ms
[root@vps1 ~]# arping -D -I eth0 -c 5 192.168.1.212 ; echo $?
ARPING 192.168.1.212 from 0.0.0.0 eth0
0
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As per arping that IP is duplicate. But if I go ahead and ifdown the
IP in the known location I cant ping that IP ( That means that IP is
not duplicated ? ). This is the result after shutting down the IP.

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[root@vps1 ~]# ping -c 3 192.168.1.212
PING 192.168.1.212 (192.168.1.212) 56(84) bytes of data.
>From 192.168.1.63 icmp_seq=1 Destination Host Unreachable
>From 192.168.1.63 icmp_seq=2 Destination Host Unreachable
>From 192.168.1.63 icmp_seq=3 Destination Host Unreachable

--- 192.168.1.212 ping statistics ---
3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 2001ms
, pipe 3
[root@vps1 ~]# arping -D -I eth0 -c 5 192.168.1.212 ; echo $?
ARPING 192.168.1.212 from 0.0.0.0 eth0
Sent 5 probes (5 broadcast(s))
Received 0 response(s)
0
[root@vps1 ~]#
--------------------------

My question is, in this case IP 192.168.1.212 is not duplicated. But
still arping gives duplicate status. Why it is like that ?

-- 
Regards,
Unni
http://mutexes.org/
http://twitter.com/webofunni