use Net::Ping;

    my $p = Net::Ping->new("icmp");
    my @host_array = (IP1,IP2,IP3...);

    foreach $host (@host_array)
    {
        print "$host is ";
        print "NOT " unless $p->ping($host, 2);
        print "reachable.\n";
        sleep(1);
    }
    $p->close();