Poor man's version of https://github.com/pete911/arpf

arpf.sh

#!/bin/bash

subnet=$1
[ -z $subnet ] && echo "Usage: $0 <subnet>" && exit 1

for host in $(seq 1 254); do
    (ping -c1 -t1 $subnet.$host > /dev/null && arp $subnet.$host) &
done

sleep 5