Download for your platform here.
(I download on my Win & copied it to openHAB2-userdata samba share)
Example for my Ubuntu server 16.04 LTS:
omr@shs2:~$ sudo dpkg -i /var/lib/openhab2/arping_2.19-1_amd64.deb
[sudo] password for omr:
(Reading database ... 68239 files and directories currently installed.)
Preparing to unpack .../arping_2.19-1_amd64.deb ...
Unpacking arping (2.19-1) over (2.14-1) ...
Setting up arping (2.19-1) ...
Removing obsolete conffile /etc/default/arping ...
Removing obsolete conffile /etc/network/if-up.d/arping ...
Processing triggers for man-db (2.7.5-1) ...
omr@shs2:~$ sudo arping -v
ARPing 2.19, by Thomas Habets <thomas@habets.se>
usage: arping [ -0aAbdDeFpPqrRuUv ] [ -w <sec> ] [ -W <sec> ] [ -S <host/ip> ]
[ -T <host/ip ] [ -s <MAC> ] [ -t <MAC> ] [ -c <count> ]
[ -C <count> ] [ -i <interface> ] [ -m <type> ] [ -g <group> ]
[ -V <vlan> ] [ -Q <priority> ] <host/ip/MAC | -B>
For complete usage info, use --help or check the manpage.