Arp Ping Networking Utility
The arping utility on Unix/Linux/Mac OS X systems is used to send an ARP request to a system on the network. IPv4 devices must respond to an ARP request, unlike a normal ping which might be declined at the firewall or other security device. ARP requests are not normally routed, so you cannot arping a device across the Internet to see if it’s up. What this means is the ARP request is not sent from one router to another, so an ARP request will fail at the router level.
To form an arping request, here is the usage:
root@thatcommunity [/sbin]# /sbin/arping Usage: arping [-fqbDUAV] [-c count] [-w timeout] [-I device] [-s source] destination -f : quit on first reply -q : be quiet -b : keep broadcasting, don't go unicast -D : duplicate address detection mode -U : Unsolicited ARP mode, update your neighbours -A : ARP answer mode, update your neighbours -V : print version and exit -c count : how many packets to send -w timeout : how long to wait for a reply -I device : which ethernet device to use (eth0) -s source : source ip address destination : ask for what ip address
When you actually use arping, the output looks like this:
root@thatcommunity [/sbin]# /sbin/arping www.learnthat.com ARPING 64.34.165.234 from 72.51.34.96 eth0 Unicast reply from 64.34.165.234 [00:00:0C:07:AC:CD] 1.406ms Unicast reply from 64.34.165.234 [00:00:0C:07:AC:CD] 2.402ms Unicast reply from 64.34.165.234 [00:00:0C:07:AC:CD] 1.887ms Unicast reply from 64.34.165.234 [00:00:0C:07:AC:CD] 5.152ms Unicast reply from 64.34.165.234 [00:00:0C:07:AC:CD] 76.378ms Unicast reply from 64.34.165.234 [00:00:0C:07:AC:CD] 2.054ms Unicast reply from 64.34.165.234 [00:00:0C:07:AC:CD] 2.322ms Unicast reply from 64.34.165.234 [00:00:0C:07:AC:CD] 48.561ms Unicast reply from 64.34.165.234 [00:00:0C:07:AC:CD] 109.788ms Sent 16 probes (1 broadcast(s)) Received 9 response(s)
You can see it received 9 responses before we canceled the arping. It shows the IP address and corresponding MAC address and the amount of time it took to receive a response.
