#!/usr/bin/perl

use warnings;
use strict;

use Net::ARP;

my $device  = q{eth0};
my %ipaddrs = ( q{192.168.1.100} => q{} );

for my $ipaddr (sort keys %ipaddrs) {
    my $mac = q{};

    Net::ARP::arp_lookup($device, $ipaddr, $mac);

    print qq{$ipaddr : $mac\n};

    Net::ARP::arp_lookup($device, $ipaddr, $mac);

    print qq{$ipaddr : $mac\n};
}