When you do a ping -c2 <you OWN ip>
you would ping only your own computer. You are not pinging for all the computer on the network. You should only get 2 pings back. (I don't know why you would do the -i30
because that will wait 30 seconds between pings.)
If you're getting DUP
s and you're on a wireless network (and you didn't ping a broadcast ip) there might be something wrong with you network.
(It is unlikely you specified a broadcast ip because you would need to specify -b
for that)
(Wireless)-networks re-send packets if they don't get proper verification. When the response on the first packet comes back all responses on the following (re-send) packets will be marked as duplicates (DUP
). In normal traffic the duplicates are discarded but in ping
they will be visible.
As you can read in the manual you shouldn't get duplicated so you might want to check if there is something wrong with you network configuration or wireless communications.
From the man ping
Duplicate and Damaged Packets
ping will report duplicate and damaged packets. Duplicate packets should never occur, and seem to be caused by inappropriate link-level retransmissions. Duplicates may occur in many situations and are rarely (if ever) a good sign, although the presence of low levels of duplicates may not always be cause for alarm.
Damaged packets are obviously serious cause for alarm and often indicate broken hardware somewhere in the ping packet's path (in the network or in the hosts).
1I tried to reword the title into something that states your problem. Please, in the future, be as clear as possible into describing what's wrong or what question you have, rather than stating you're a novice in all-caps. Thanks. – slhck – 2013-11-22T23:11:53.510